Powered surgical stapling device

ABSTRACT

A surgical stapler includes a handle assembly, an end effector, a firing rod disposed in mechanical cooperation with the end effector, a drive motor coupled to the firing rod, a sensor, and a controller. The end effector includes a first and second jaw member moveable relative to one another. The first jaw member includes a surgical fastener and the second jaw member includes an anvil. The drive motor is configured to advance the firing rod to cause the first and second jaw members to clamp tissue and to eject a surgical fastener. The surgical stapler includes a sensor that is configured measure a clamping force exerted on tissue by the first and second jaw members. The controller control a speed of the drive motor based on the measured clamping force.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/598,586, which was filed on Jan. 16, 2015, which is acontinuation-in-part of U.S. patent application Ser. No. 13/788,293,which was filed on Mar. 7, 2013, which is a continuation-in-part of U.S.patent application Ser. No. 12/189,834, which was filed on Aug. 12,2008, now abandoned, which claims the benefit of, and priority to, U.S.Provisional Patent Application Ser. No. 60/997,854, which was filed onOct. 5, 2007. This application is also a continuation-in-part of U.S.patent application Ser. No. 15/585,699, which was filed on May 3, 2017,which is a continuation-in-part of U.S. patent application Ser. No.14/808,672, filed Jul. 24, 2015, now U.S. Pat. No. 9,433,418, which is acontinuation of U.S. patent application Ser. No. 14/694,354, filed Apr.23, 2015, now U.S. Pat. No. 9,113,877, which is a continuation of U.S.patent application Ser. No. 13/933,299, filed Jul. 2, 2013, now U.S.Pat. No. 9,016,540, which is a continuation of U.S. patent applicationSer. No. 13/486,370, filed Jun. 1, 2012, now U.S. Pat. No. 8,499,992,which is a continuation of U.S. patent application Ser. No. 13/197,097,filed on Aug. 3, 2011, now U.S. Pat. No. 8,210,413, which is adivisional of U.S. patent application Ser. No. 12/430,780, filed on Apr.27, 2009, now U.S. Pat. No. 8,012,170. The entire contents of each ofthe foregoing applications are hereby incorporated by reference herein.

BACKGROUND

1. Technical Field

The present disclosure relates to a surgical stapler for implantingmechanical surgical fasteners into the tissue of a patient, and, inparticular, to a surgical stapler which is powered by a motor for firingsurgical fasteners into tissue and a feedback controller for controllingthe stapler in response to one or more sensed feedback signals.

2. Background of Related Art

Current known devices can typically require 10-60 pounds of manual handforce to clamp tissue and deploy and form surgical fasteners in tissuewhich, over repeated use, can cause a surgeon's hand to become fatigued.Gas powered pneumatic staplers which implant surgical fasteners intotissue are known in the art. Certain of these instruments utilize apressurized gas supply which connects to a trigger mechanism. Thetrigger mechanism, when depressed, simply releases pressurized gas toimplant a fastener into tissue.

Motor-powered surgical staplers are also known in the art. These includepowered surgical staplers having motors which activate staple firingmechanisms. However, these motor powered devices only provide forlimited user control of the stapling process. The user can only toggle asingle switch and/or button to actuate the motor and apply correspondingtorque to the stapler's firing mechanisms. In certain other devices, acontroller is used to control the stapler.

There is a continual need for new and improved powered surgical staplerswhich include various sensors. The sensors provide relevant feedback tofeedback controllers which automatically adjust various parameters ofthe powered stapler in response to sensed feedback signalsrepresentative of stapler operation.

SUMMARY

According to one aspect of the present disclosure, a surgical staplerincludes a handle assembly, an end effector coupled to the handleassembly, a firing rod disposed in mechanical cooperation with the endeffector, a drive motor coupled to the firing rod, a sensor, and acontroller operatively coupled to the drive motor. The end effectorincludes a first jaw member including a surgical fastener and a secondjaw member including an anvil portion. The first and second jaw membersare moveable relative to one another between an open position and aclamped position. The drive motor is configured to advance the firingrod to cause the first and second jaw members to clamp tissue and toeject a surgical fastener. The sensor is configured to measure aclamping force exerted on tissue by the first and second jaw members. Inanother aspect, the sensor is configured to measure a firing forceexerted on the surgical fastener. The controller is configured tocontrol a speed of the drive motor based on the measured clamping force.

According to further aspects of the present disclosure, the controlleris further configured to set the speed of the drive motor to a firstfiring speed in response to the measured clamping force being between afirst threshold clamping force and a second threshold clamping force. Inaspects, the first threshold clamping force may be about 0 pound-force(lbf) and the second threshold clamping force may be about 33 lbf, inembodiments the first threshold clamping force may be about 33 lbf andthe second threshold clamping force may be about 72 lbf, and in otherembodiments the first threshold clamping force may be about about 72 lbfand the second threshold clamping force may be about 145 lbf.

In one aspect of the present disclosure, the controller is furtherconfigured to stop the drive motor in response to the measured clampingforce being greater than a first threshold clamping force. In aspects,the first threshold clamping force is about 145 lbf.

According to yet further aspects of the present disclosure, thecontroller is further configured to set the speed of the drive motor toa second firing speed in response to the measured firing force beingbetween a first firing force threshold and a second firing forcethreshold. In aspects, the first firing force threshold is about 0 lbfand the second firing force threshold is about 65 lbf, in embodimentsthe first firing force threshold is about 65 lbf and the second firingforce threshold is about 80 lbf, and in other embodiments the firstfiring force threshold is about 80 lbf and the second firing forcethreshold is about 145 lbf.

In one aspect of the present disclosure, if the firing force is greaterthan a first firing force threshold, the controller stops the drivemotor. In aspects, the first firing force threshold is about 145 lbf.

According to yet further aspects of the present disclosure, the sensoris a strain gauge sensor disposed on at least one of the first jawmember, the second jaw member, or the firing rod. The strain gaugesensor is configured to measure the clamping force by monitoring a speedof the drive motor, a torque being applied by the drive motor, distancebetween the first and second jaw members, monitoring the temperature ofone or more components of the surgical stapler, or a load on the firingrod.

According to a further aspect of the present disclosure, a method forcontrolling the firing speed of a surgical stapler is disclosed. Themethod comprises positioning tissue between a first jaw member and asecond jaw member of an end effector, the first and second jaw membersbeing moveable relative to one another and the first jaw memberincluding a staple cartridge. The method further comprises measuring amaximum clamp force of the first and second jaw members on the tissue,setting a first firing speed of a staple from the staple cartridge basedon the measured maximum clamp force, initiating the firing of the staplefrom the staple cartridge, measuring a firing force exerted on thestaple, and adjusting the first firing speed of the surgical stapler toa second firing speed based on the measured firing force.

In some aspects of the present disclosure, the method includes stoppingthe firing of the staple from the staple cartridge if the measuredfiring force is greater than a first firing force threshold. In aspects,the first firing force threshold is about 145 lbf.

In some aspects of the present disclosure, the maximum clamp force ismeasured by a sensor configured to measure the clamping force bymonitoring a speed of the drive motor, a torque being applied by thedrive motor, a distance between the first and second jaw members, or aload on the firing rod.

Further, to the extent consistent, any of the aspects described hereinmay be used in conjunction with any or all of the other aspectsdescribed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1 is a perspective view of a powered surgical instrument accordingto an embodiment of the present disclosure;

FIG. 2 is a partial enlarged perspective view of the powered surgicalinstrument according to the embodiment of the present disclosure of FIG.1;

FIG. 3 is a partial enlarged plan view of the powered surgicalinstrument according to the embodiment of the present disclosure of FIG.1;

FIG. 4 is a partial perspective sectional view of internal components ofthe powered surgical instrument of FIG. 1 in accordance with anembodiment of the present disclosure;

FIG. 5 is a perspective view of an articulation mechanism with partsseparated of the powered surgical instrument of FIG. 1 in accordancewith an embodiment of the present disclosure;

FIG. 6 is a partial cross-sectional view showing internal components ofthe powered surgical instrument according to the embodiment of thepresent disclosure of FIG. 1 disposed in a first position;

FIG. 7 is a partial cross-sectional view showing internal components ofthe powered surgical instrument according to the embodiment of thepresent disclosure of FIG. 1 disposed in a second position;

FIG. 8 is a perspective view of the mounting assembly and the proximalbody portion of a loading unit with parts separated of the poweredsurgical instrument of FIG. 1 in accordance with an embodiment of thepresent disclosure;

FIG. 9 is a side cross-sectional view of an end effector of the poweredsurgical instrument of FIG. 1 in accordance with an embodiment of thepresent disclosure;

FIG. 10 is a partial enlarged side view showing internal components ofthe powered surgical instrument according to the embodiment of thepresent disclosure of FIG. 1;

FIG. 11 is a perspective view of a unidirectional clutch plate of thepowered surgical instrument of FIG. 1 in accordance with an embodimentof the present disclosure;

FIG. 12 is a partial enlarged side view showing internal components ofthe powered surgical instrument according to the embodiment of thepresent disclosure of FIG. 1;

FIG. 13 is a schematic diagram of a power source of the powered surgicalinstrument according to the embodiment of the present disclosure of FIG.1;

FIG. 14 is a flow chart diagram illustrating a method for authenticatingthe power source of the powered surgical instrument of FIG. 1;

FIGS. 15A-B are partial perspective rear views of a loading unit of thepowered surgical instrument according to the embodiment of the presentdisclosure of FIG. 1;

FIG. 16 is a flow chart diagram illustrating a method for authenticatingthe loading unit of the powered surgical instrument according to theembodiment of the present disclosure of FIG. 1;

FIG. 17 is a perspective view of the loading unit of the poweredsurgical instrument according to the embodiment of the presentdisclosure of FIG. 1;

FIG. 18 is a side cross-sectional view of the end effector of thepowered surgical instrument of FIG. 1 in accordance with an embodimentof the present disclosure;

FIG. 19 is a side cross-sectional view of the powered surgicalinstrument of FIG. 1 in accordance with an embodiment of the presentdisclosure;

FIG. 20 is a schematic diagram of a control system of the poweredsurgical instrument according to the embodiment of the presentdisclosure of FIG. 1;

FIG. 21 is a schematic diagram of a feedback control system according tothe present disclosure;

FIGS. 22A-B are perspective front and rear views of a feedbackcontroller of the feedback control system according to the embodiment ofthe present disclosure;

FIG. 23 is a schematic diagram of the feedback controller according tothe embodiment of the present disclosure;

FIG. 24 is a partial sectional view of internal components of a poweredsurgical instrument in accordance with an embodiment of the presentdisclosure;

FIG. 25 is a partial perspective sectional view of internal componentsof the powered surgical instrument in accordance with an embodiment ofthe present disclosure;

FIG. 26 is a partial perspective view of a nose assembly of the poweredsurgical instrument in accordance with an embodiment of the presentdisclosure;

FIG. 27 is a partial perspective view of a retraction lever of thepowered surgical instrument in accordance with an embodiment of thepresent disclosure;

FIG. 28 is a partial perspective view of the powered surgical instrumentin accordance with an embodiment of the present disclosure;

FIG. 29 is a perspective view of the powered surgical instrument inaccordance with an embodiment of the present disclosure;

FIG. 30 is a perspective view of a modular retraction assembly of thepowered surgical instrument in accordance with an embodiment of thepresent disclosure;

FIG. 31 is an enlarged partial sectional view of internal components ofa powered surgical instrument in accordance with an embodiment of thepresent disclosure;

FIG. 32 is an enlarged partial sectional view of internal components ofa powered surgical instrument in accordance with an embodiment of thepresent disclosure;

FIG. 33 is a side cross-sectional view of an embodiment of an endeffector of the powered surgical instrument of FIG. 1 in accordance withthe present disclosure;

FIG. 34 is a rear cross-sectional view taken along the section line ofFIG. 33;

FIG. 35 is a rear cross-sectional view of another end effector inaccordance with an embodiment of the present disclosure;

FIG. 36 a rear cross-sectional view of yet another embodiment of an endeffector of the powered surgical instrument of FIG. 1 in accordance withthe present disclosure;

FIG. 37 is a chart showing the responsivity of the wavelengths of light;

FIG. 38 is a side cross-sectional view of another end effector of thepowered surgical instrument of FIG. 1 in accordance with an embodimentof the present disclosure;

FIG. 39 is a cross-sectional view taken along the section line of FIG.38.

FIG. 40 is a schematic diagram of a control system of the poweredsurgical instrument according to the embodiment of the presentdisclosure of FIG. 1;

FIG. 41 is a graph illustrating force applied over time by the poweredsurgical instrument of FIG. 1 in accordance with an embodiment of thepresent disclosure;

FIG. 42 is a flowchart illustrating a method for controlling the poweredsurgical instrument of FIG. 1 in accordance with an embodiment of thepresent disclosure; and

FIG. 43 is a graph illustrating firing speed over force applied by thepowered surgical instrument in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Embodiments of the presently disclosed powered surgical instrument arenow described in detail with reference to the drawings, in which likereference numerals designate identical or corresponding elements in eachof the several views. As used herein the term “distal” refers to thatportion of the powered surgical instrument, or component thereof,farther from the user while the term “proximal” refers to that portionof the powered surgical instrument or component thereof, closer to theuser.

A powered surgical instrument, e.g., a surgical stapler, in accordancewith the present disclosure is referred to in the figures as referencenumeral 10. Referring initially to FIG. 1, powered surgical instrument10 includes a housing 110, an endoscopic portion 140 defining a firstlongitudinal axis A-A extending therethrough, and an end effector 160,defining a second longitudinal axis B-B extending therethrough.Endoscopic portion 140 extends distally from housing 110 and the endeffector 160 is disposed adjacent a distal portion of endoscopic portion140. In an embodiment, the components of the housing 110 are sealedagainst infiltration of particulate and/or fluid contamination and helpprevent damage of the component by the sterilization process.

According to an embodiment of the present disclosure, end effector 160includes a first jaw member having one or more surgical fasteners (e.g.,cartridge assembly 164) and a second opposing jaw member including ananvil portion for deploying and forming the surgical fasteners (e.g., ananvil assembly 162). In certain embodiments, the staples are housed incartridge assembly 164 to apply linear rows of staples to body tissueeither in simultaneous or sequential manner. Either one or both of theanvil assembly 162 and the cartridge assembly 164 are movable inrelation to one another between an open position in which the anvilassembly 162 is spaced from cartridge assembly 164 and an approximatedor clamped position in which the anvil assembly 162 is in juxtaposedalignment with cartridge assembly 164.

It is further envisioned that end effector 160 is attached to a mountingportion 166, which is pivotably attached to a body portion 168. Bodyportion 168 may be integral with endoscopic portion 140 of poweredsurgical instrument 10, or may be removably attached to the instrument10 to provide a replaceable, disposable loading unit (DLU) or single useloading unit (SULU) (e.g., loading unit 169). In certain embodiments,the reusable portion may be configured for sterilization and re-use in asubsequent surgical procedure.

The loading unit 169 may be connectable to endoscopic portion 140through a bayonet connection. It is envisioned that the loading unit 169has an articulation link connected to mounting portion 166 of theloading unit 169 and the articulation link is connected to a linkage rodso that the end effector 160 is articulated as the linkage rod istranslated in the distal-proximal direction along first longitudinalaxis A-A. Other means of connecting end effector 160 to endoscopicportion 140 to allow articulation may be used, such as a flexible tubeor a tube comprising a plurality of pivotable members.

The loading unit 169 may incorporate or be configured to incorporatevarious end effectors, such as vessel sealing devices, linear staplingdevices, circular stapling devices, cutters, etc. Such end effectors maybe coupled to endoscopic portion 140 of powered surgical instrument 10.The loading unit 169 may include a linear stapling end effector thatdoes not articulate. An intermediate flexible shaft may be includedbetween handle portion 112 and loading unit. It is envisioned that theincorporation of a flexible shaft may facilitate access to and/or withincertain areas of the body.

With reference to FIG. 2, an enlarged view of the housing 110 isillustrated according to an embodiment of the present disclosure. In theillustrated embodiment, housing 110 includes a handle portion 112 havinga main drive switch 114 disposed thereon. The switch 114 may includefirst and second switches 114 a and 114 b formed together as a toggleswitch. The handle portion 112, which defines a handle axis H-H, isconfigured to be grasped by fingers of a user. The handle portion 112has an ergonomic shape providing ample palm grip leverage which helpsprevent the handle portion 112 from being squeezed out of the user'shand during operation. Each switch 114 a and 114 b is shown as beingdisposed at a suitable location on handle portion 112 to facilitate itsdepression by a user's finger or fingers.

Additionally, and with reference to FIGS. 1 and 2, switches 114 a, 114 bmay be used for starting and/or stopping movement of drive motor 200(FIG. 4). In one embodiment, the switch 114 a is configured to activatethe drive motor 200 in a first direction to advance firing rod 220 (FIG.6) in a distal direction thereby clamping the anvil and the cartridgeassemblies 162 and 164. Conversely, the switch 114 b may be configuredto retract the firing rod 220 to open the anvil and cartridge assemblies162 and 164 by activating the drive motor 200 in a reverse direction.The retraction mode initiates a mechanical lock out, preventing furtherprogression of stapling and cutting by the loading unit 169. The togglehas a first position for activating switch 114 a, a second position foractivating switch 114 b, and a neutral position between the first andsecond positions. The details of operation of the drive components ofthe instrument 10 are discussed in more detail below.

The housing 110, in particular the handle portion 112, includes switchshields 117 a and 117 b. The switch shields 117 a and 117 b may have arib-like shape surrounding the bottom portion of the switch 114 a andthe top portion of the switch 114 b, respectively. The switch shields117 a and 117 b prevent accidental activation of the switch 114.Further, the switches 114 a and 114 b have high tactile feedbackrequiring increased pressure for activation.

In one embodiment, the switches 114 a and 114 b are configured asmulti-speed (e.g., two or more), incremental or variable speed switcheswhich control the speed of the drive motor 200 and the firing rod 220 ina non-linear manner. For example, switches 114 a, 114 b can bepressure-sensitive. This type of control interface allows for gradualincrease in the rate of speed of the drive components from a slower andmore precise mode to a faster operation. To prevent accidentalactivation of retraction, the switch 114 b may be disconnectedelectronically until a fail safe switch is pressed. In addition a thirdswitch 114 c may also be used for this purpose. Additionally oralternatively, the fail safe can be overcome by pressing and holding theswitch 114 b for a predetermined period of time from about 100 ms toabout 2 seconds. The firing rod 220 then automatically retracts to itsinitial position unless the switch 114 b is activated (e.g., pressed andreleased) during the retraction mode to stop the retraction. Subsequentpressing of the switch 114 b after the release thereof resumes theretraction. Alternatively, the retraction of the firing rod 220 cancontinue to full retraction even if the switch 114 b is released, inother embodiments.

The switches 114 a and 114 b are coupled to a non-linear speed controlcircuit 115 which can be implemented as a voltage regulation circuit, avariable resistance circuit, or a microelectronic pulse width modulationcircuit. The switches 114 a and 144 b may interface with the controlcircuit 115 by displacing or actuating variable control devices, such asrheostatic devices, multiple position switch circuit, linear and/orrotary variable displacement transducers, linear and/or rotarypotentiometers, optical encoders, ferromagnetic sensors, and/or HallEffect sensors. This allows the switches 114 a and 114 b to operate thedrive motor 200 in multiple speed modes, such as gradually increasingthe speed of the drive motor 200 either incrementally or graduallydepending on the type of the control circuit 115 being used, based onthe depression of the switches 114 a and 114 b.

In a particular embodiment, the switch 114 c may also be included (FIGS.1, 2 and 4), wherein depression thereof may mechanically and/orelectrically change the mode of operation from clamping to firing. Theswitch 114 c is recessed within the housing 110 and has high tactilefeedback to prevent false actuations. Providing of a separate controlswitch to initialize the firing mode allows for the jaws of the endeffector to be repeatedly opened and closed, so that the instrument 10is used as a grasper until the switch 114 c is pressed, thus activatingthe stapling and/or cutting. The switch 114 may include one or moremicroelectronic membrane switches, for example. Such a microelectronicmembrane switch includes a relatively low actuation force, small packagesize, ergonomic size and shape, low profile, the ability to includemolded letters on the switch, symbols, depictions and/or indications,and a low material cost. Additionally, switches 114 (such asmicroelectronic membrane switches) may be sealed to help facilitatesterilization of the instrument 10, as well as helping to preventparticle and/or fluid contamination.

As an alternative to, or in addition to switches 114, other inputdevices may include voice input technology, which may include hardwareand/or software incorporated in a control system 501 (FIG. 14), or aseparate digital module connected thereto. The voice input technologymay include voice recognition, voice activation, voice rectification,and/or embedded speech. The user may be able to control the operation ofthe instrument in whole or in part through voice commands, thus freeingone or both of the user's hands for operating other instruments. Voiceor other audible output may also be used to provide the user withfeedback.

Referring to FIG. 3, a proximal area 118 of housing 110 having a userinterface 120 is shown. The user interface 120 includes a screen 122 anda plurality of switches 124. The user interface 120 may display varioustypes of operational parameters of the instrument 10 such as “mode”(e.g., rotation, articulation or actuation), which may be communicatedto user interface via a sensor, “status” (e.g., angle of articulation,speed of rotation, or type of actuation) and “feedback,” such as whetherstaples have been fired based on the information reported by the sensorsdisposed in the instrument 10.

The screen 122 may be an LCD screen, a plasma screen, electroluminescentscreen and the like. In one embodiment the screen 122 may be a touchscreen, obviating the need for the switches 124. The touch screen mayincorporate resistive, surface wave, capacitive, infrared, strain gauge,optical, dispersive signal or acoustic pulse recognition touch screentechnologies. The touch screen may be used to allow the user to provideinput while viewing operational feedback. This approach may enablefacilitation of sealing screen components to help sterilize theinstrument 10, as well as preventing particle and/or fluidcontamination. In certain embodiments, screen is pivotably or rotatablymounted to the instrument 10 for flexibility in viewing screen duringuse or preparation (e.g., via a hinge or ball-and-socket mount).

The switches 124 may be used for starting and/or stopping movement ofthe instrument 10 as well as selecting the pivot direction, speed and/ortorque. It is also envisioned that at least one switch 124 can be usedfor selecting an emergency mode that overrides various settings. Theswitches 124 may also be used for selecting various options on thescreen 122, such as responding to prompts while navigating userinterface menus and selecting various settings, allowing a user inputdifferent tissue types, and various sizes and lengths of staplecartridges.

The switches 124 may be formed from a micro-electronic tactile ornon-tactile membrane, a polyester membrane, elastomer, plastic or metalkeys of various shapes and sizes. Additionally, switches may bepositioned at different heights from one another and/or may includeraised indicia or other textural features (e.g., concavity or convexity)to allow a user to depress an appropriate switch without the need tolook at user interface 120.

In addition to the screen 122, the user interface 120 may include one ormore visual outputs 123 which may include one or more colored visiblelights or light emitting diodes (“LED”) to relay feedback to the user.The visual outputs 123 may include corresponding indicators of variousshapes, sizes and/or colors having numbers and/or text which identifythe visual outputs 123. The visual outputs 123 are disposed on top ofthe housing 110 such that the outputs 123 are raised and protrude inrelation to the housing 110 providing for better visibility thereof.

The multiple lights display in a certain combination to illustrate aspecific operational mode to the user. In one embodiment, the visualoutputs 123 include a first light (e.g., yellow) 123 a, a second light(e.g., green) 123 b and a third light (e.g., red) 123 c. The lights areoperated in a particular combination associated with a particularoperational mode as listed in Table 1 below.

TABLE 1 Light Combination Operational Mode Light Status No loading unit169 or staple cartridge First Light Off is loaded. Second Light OffThird Light Off Light Status The loading unit 169 and/or staplecartridge First Light On are loaded and power is activated, allowingSecond Light Off the end effector 160 to clamp as a Third Light Offgrasper and articulate. Light Status A used loading unit 169 or stapleFirst Light Flashing cartridge is loaded. Second Light Off Third LightOff Light Status Instrument 10 is deactivated and First Light N/Aprevented from firing staples Second Light Off or cutting. Third LightN/A Light Status A new loading unit 169 is loaded, the end First LightOn effector 160 is fully clamped and the Second Light On instrument 10is in firing staple and cutting Third Light Off modes. Light Status Dueto high stapling forces a pulse First Light On mode is in effect,providing for a time Second Light Flashing delay during which tissue iscompressed. Third Light Off Light Status No system errors detected.First Light N/A Second Light N/A Third Light Off Light Status Tissuethickness and/or firing load is too First Light On high, this warningcan be overridden. Second Light On Third Light On Light StatusFunctional system error is detected, First Light N/A instrument 10should be replaced. Second Light N/A Third Light Flashing

In another embodiment, the visual output 123 may include a singlemulti-colored LED which displays a particular color associated with theoperational modes as discussed above with respect to the first, secondand third lights in Table 1.

The user interface 120 also includes audio outputs 125 (e.g., tones,bells, buzzers, integrated speaker, etc.) to communicate various statuschanges to the user such as lower battery, empty cartridge, etc. Theaudible feedback can be used in conjunction with or in lieu of thevisual outputs 123. The audible feedback may be provided in the forms ofclicks, snaps, beeps, rings and/or buzzers in single or multiple pulsesequences. In one embodiment, a simulated mechanical sound may beprerecorded which replicates the click and/or snap sounds generated bymechanical lockouts and mechanisms of conventional non-poweredinstruments. This eliminates the need to generate such mechanical soundsthrough the actual components of the instrument 10 and also avoids theuse of beeps and other electronic sounds which are usually associatedwith other operating room equipment, thereby preventing confusion fromextraneous audible feedback.

The instrument 10 may also provide for haptic or vibratory feedbackthrough a haptic mechanism (not explicitly shown) within the housing110. The haptic feedback may be used in conjunction with the auditoryand visual feedback or in lieu thereof to avoid confusion with theoperating room equipment which relies on audio and visual feedback. Thehaptic mechanism may be an asynchronous motor that vibrates in apulsating manner. In one embodiment, the vibrations are at a frequencyof about 30 Hz or above providing a displacement having an amplitude of1.5 mm or lower to limit the vibratory effects from reaching the loadingunit 169.

It is also envisioned that user interface 120 includes different colorsand/or intensities of text on screen and/or on switches for furtherdifferentiation between the displayed items. The visual, auditory orhaptic feedback can be increased or decreased in intensity. For example,the intensity of the feedback may be used to indicate that the forces onthe instrument are becoming excessive.

FIGS. 2-4 illustrate an articulation mechanism 170, including anarticulation housing 172, a powered articulation switch 174, anarticulation motor 132, and a manual articulation knob 176. Translationof the powered articulation switch 174 or pivoting of the manualarticulation knob 176 activates the articulation motor 132 which thenactuates an articulation gear 233 of the articulation mechanism 170 asshown in FIG. 4. Actuation of articulation mechanism 170 causes the endeffector 160 to move from its first position, where longitudinal axisB-B is substantially aligned with longitudinal axis A-A, towards aposition in which longitudinal axis B-B is disposed at an angle tolongitudinal axis A-A. Preferably, a plurality of articulated positionsis achieved. The powered articulation switch 174 may also incorporatesimilar non-linear speed controls as the clamping mechanism ascontrolled by the switches 114 a and 114 b.

Further, the housing 110 includes switch shields 169 having a wing-likeshape and extending from the top surface of the housing 110 over theswitch 174. The switch shields 169 prevent accidental activation of theswitch 174 and require the user to reach below the shield 169 in orderto activate the articulation mechanism 170.

Additionally, articulation housing 172 and powered articulation switch174 are mounted to a rotating housing assembly 180. Rotation of arotation knob 182 about first longitudinal axis A-A causes housingassembly 180 as well as articulation housing 172 and poweredarticulation switch 174 to rotate about first longitudinal axis A-A, andthus causes corresponding rotation of distal portion 224 of firing rod220 and end effector 160 about first longitudinal axis A-A. Thearticulation mechanism 170 is electro-mechanically coupled to first andsecond conductive rings 157 and 159 which are disposed on the housingnose assembly 155 as shown in FIGS. 4 and 26. The conductive rings 157and 159 may be soldered and/or crimped onto the nose assembly 155 andare in electrical contact with the power source 400 thereby providingelectrical power to the articulation mechanism 170. The nose assembly155 may be modular and may be attached to the housing 110 duringassembly to allow for easier soldering and/or crimping of the rings. Thearticulation mechanism 170 includes one or more brush and/or springloaded contacts in contact with the conductive rings 157 and 159 suchthat as the housing assembly 180 is rotated along with the articulationhousing 172 the articulation mechanism 170 is in continuous contact withthe conductive rings 157 and 159 thereby receiving electrical power fromthe power source 400.

Further details of articulation housing 172, powered articulation switch174, manual articulation knob 176 and providing articulation to endeffector 160 are described in detail in commonly-owned U.S. PatentApplication Publication No. 2008/0223903A1 filed Mar. 15, 2007, thecontents of which are hereby incorporated by reference in theirentirety. It is envisioned that any combinations of limit switches,proximity sensors (e.g., optical and/or ferromagnetic), linear variabledisplacement transducers and/or shaft encoders which may be disposedwithin housing 110, may be utilized to control and/or record anarticulation angle of end effector 160 and/or position of the firing rod220.

FIGS. 4-8 illustrate various internal components of the instrument 10,including a drive motor 200, a drive tube 210 and a firing rod 220having a proximal portion 222 and a distal portion 224. The drive tube210 is rotatable about drive tube axis C-C extending therethrough. Drivemotor 200 is disposed in mechanical cooperation with drive tube 210 andis configured to rotate the drive tube 210 about drive gear axis C-C. Inone embodiment, the drive motor 200 may be an electrical motor or a gearmotor, which may include gearing incorporated within its housing.

The housing 110 may be formed from two halves 110 a and 110 b asillustrated in FIG. 3. The two housing portion halves 110 a and 110 bmay be attached to each other using screws at boss locators 111 whichalign the housing portions 110 a and 110 b. In addition, the housing 110may be formed from plastic and may include rubber support membersapplied to the internal surface of the housing 110 via a two-shotmolding process. The rubber support members may isolate the vibration ofthe drive components (e.g., drive motor 200) form the rest of theinstrument 10.

The housing halves 110 a and 110 b may be attached to each via a thinsection of plastic (e.g., a living hinge) that interconnects the halves110 a and 110 b allowing the housing 110 to be opened by breaking awaythe halves 110 a and 110 b.

In one embodiment, the drive components (e.g., including a drive motor200, a drive tube 210, a firing rod 220, etc.) may be mounted on asupport plate allowing the drive components to be removed from thehousing 110 after the instrument 10 has been used. The support platemounting in conjunction with the hinged housing halves 110 a and 110 bprovide for reusability and recyclability of specific internalcomponents while limiting contamination thereof.

With reference to FIGS. 4-6, a firing rod coupling 190 is illustrated.Firing rod coupling 190 provides a link between the proximal portion 222and the distal portion 224 of the firing rod 220. Specifically, thefiring rod coupling 190 enables rotation of the distal portion 224 ofthe firing rod 220 with respect to proximal portion 222 of firing rod220. Thus, firing rod coupling 190 enables proximal portion 222 offiring rod 220 to remain non-rotatable, as discussed below withreference to an alignment plate 350, while allowing rotation of distalportion 224 of firing rod 220 (e.g., upon rotation of rotation knob182).

With reference to FIGS. 5 and 6, the proximal portion 222 of firing rod220 includes a threaded portion 226, which extends through aninternally-threaded portion 212 of drive tube 210. This relationshipbetween firing rod 220 and drive tube 210 causes firing rod 220 to movedistally and/or proximally, in the directions of arrows D and E, alongthreaded portion 212 of drive tube 210 upon rotation of drive tube 210in response to the rotation of the drive motor 200. As the drive tube210 rotates in a first direction (e.g., clockwise), firing rod 220 movesproximally as illustrated in FIG. 6, and the firing rod 220 is disposedat its proximal-most position. As the drive tube 210 rotates in a seconddirection (e.g., counter-clockwise), firing rod 220 moves distally asillustrated in FIG. 7, and the firing rod 220 is disposed at itsdistal-most position.

The firing rod 220 is distally and proximally translatable withinparticular limits. Specifically, a first end 222 a of proximal portion222 of firing rod 220 acts as a mechanical stop in combination with analignment plate 350. That is, upon retraction when firing rod 220 istranslated proximally, first end 222 a contacts a distal surface 351 ofalignment plate 350, thus preventing continued proximal translation offiring rod 220 as shown in FIG. 5. Additionally, threaded portion 226 ofthe proximal portion 222 acts as a mechanical stop in combination withalignment plate 350. That is, when firing rod 220 is translateddistally, the threaded portion 226 contacts a proximal surface 353 ofthe alignment plate 350, thus preventing further distal translation offiring rod 220 as shown in FIG. 6. The alignment plate 350 includes anaperture therethrough, which has a non-round cross-section. Thenon-round cross-section of the aperture prevents rotation of proximalportion 222 of firing rod 220, thus limiting proximal portion 222 offiring rod 220 to axial translation therethrough. Further, a proximalbearing 354 and a distal bearing 356 are disposed at least partiallyaround drive tube 210 for facilitation of rotation of drive tube 210,while helping align drive tube 210 within housing 110.

Rotation of drive tube 210 in a first direction (e.g.,counter-clockwise) corresponds with distal translation of the firing rod220 which actuates jaw members 162, 164 of the end effector 160 to graspor clamp tissue held therebetween. Additional distal translation offiring rod 220 ejects surgical fasteners from the end effector 160 tofasten tissue by actuating cam bars and/or an actuation sled 74 (FIG.9). Further, the firing rod 220 may also be configured to actuate aknife (not explicitly shown) to sever tissue. Proximal translation offiring rod 220 corresponding with rotation of the drive tube 210 in asecond direction (e.g., clockwise) actuates jaw members 162, 164 and/orknife to retract or return to corresponding pre-fired positions. Furtherdetails of firing and otherwise actuating end effector 160 are describedin detail in commonly-owned U.S. Pat. No. 6,953,139 to Milliman et al.(“the '139 Milliman Patent”), the disclosure of which is herebyincorporated by reference herein.

FIG. 8 shows an exploded view of the loading unit 169. The end effector160 may be actuated by an axial drive assembly 213 having a drive beamor drive beam 266. The distal end of the drive beam 213 may include aknife blade. In addition, the drive beam 213 includes a retention flange40 having a pair of cam members 40 a which engage the anvil and thecartridge assembly 162 and 164 during advancement of the drive beam 213longitudinally. The drive beam 213 advances an actuation sled 74longitudinally through the staple cartridge 164. The sled 74 has camwedges for engaging pushers 68 disposed in slots of the cartridgeassembly 164, as the sled 74 is advanced. Staples 66 disposed in theslots are driven through tissue and against the anvil assembly 162 bythe pushers 68.

With reference to FIG. 8, a drive motor shaft 202 is shown extendingfrom a planetary gear 204 that is attached to drive motor 200. Drivemotor shaft 202 is in mechanical cooperation with clutch 300. Drivemotor shaft 202 is rotated by the drive motor 200, thus resulting inrotation of clutch 300. Clutch 300 includes a clutch plate 302 and aspring 304 and is shown having wedged portions 306 disposed on clutchplate 302, which are configured to mate with an interface (e.g., wedges214) disposed on a proximal face 216 of drive tube 210.

Spring 304 is illustrated between planetary gear 204 and drive tube 210.Specifically, and in accordance with the embodiment illustrated in FIG.8, spring 304 is illustrated between clutch face 302 and a clutch washer308. Additionally, drive motor 200 and planetary gear 204 are mounted ona motor mount 310. As illustrated in FIG. 8, motor mount 310 isadjustable proximally and distally with respect to housing 110 via slots312 disposed in motor mount 310 and protrusions 314 disposed on housing110.

In an embodiment of the disclosure, the clutch 300 is implemented as aslip unidirectional clutch to limit torque and high inertia loads on thedrive components. Wedged portions 306 of clutch 300 are configured andarranged to slip with respect to wedges 214 of proximal face 216 ofdrive tube 210 unless a threshold force is applied to clutch plate 302via clutch spring 304. Further, when spring 304 applies the thresholdforce needed for wedged portions 306 and wedges 214 to engage withoutslipping, drive tube 210 will rotate upon rotation of drive motor 200.It is envisioned that wedged portions 306 and/or wedges 214 areconfigured to slip in one and/or both directions (i.e., clockwise and/orcounter-clockwise) with respect to one another until a threshold forceis attained.

As illustrated in FIGS. 11 and 12, the clutch 300 is shown with aunidirectional clutch plate 700. The clutch plate 700 includes aplurality of wedged portions 702 having a slip face 704 and a grip face706. The slip face 704 has a curved edge which engages the wedges 214 ofthe drive tube 210 up to a predetermined load. The grip face 706 has aflat edge which fully engages the drive tube 210 and prevents slippage.When the clutch plate 700 is rotated in a first direction (e.g.,clockwise) the grip face 706 of the wedged portions 702 engage thewedges 214 without slipping, providing for full torque from the drivemotor 200. When the clutch plate 700 is rotated in a reverse direction(e.g., counterclockwise) the slip face 704 of the wedged portions 702engage the wedges 214 and limit the torque being transferred to thedrive tube 210. Thus, if the load being applied to the slip face 704 isover the limit, the clutch 300 slips and the drive tube 210 is notrotated. This prevents high load damage to the end effector 160 ortissue which can occur due to the momentum and dynamic friction of thedrive components. More specifically, the drive mechanism of theinstrument 10 can drive the drive rod 220 in a forward direction withless torque than in reverse. Use of a unidirectional clutch eliminatesthis problem. In addition, an electronic clutch may also be used toincrease the motor potential during retraction (e.g., driving the driverod 220 in reverse) as discussed in more detail below.

It is further envisioned that drive motor shaft 202 includes a D-shapedcross-section 708, which includes a substantially flat portion 710 and arounded portion 712. Thus, while drive motor shaft 202 is translatablewith respect to clutch plate 302, drive motor shaft 202 will not “slip”with respect to clutch plate 302 upon rotation of drive motor shaft 202.That is, rotation of drive motor shaft 202 will result in a slip-lessrotation of clutch plate 302.

The loading unit, in certain embodiments according to the presentdisclosure, includes an axial drive assembly that cooperates with firingrod 220 to approximate anvil assembly 162 and cartridge assembly 164 ofend effector 160, and fire staples 66 from the staple cartridge. Theaxial drive assembly may include a beam that travels distally throughthe staple cartridge and may be retracted after the staples 66 have beenfired, as discussed above and as disclosed in certain embodiments of the'139 Milliman Patent.

With reference to FIG. 4, the instrument 10 includes a power source 400which may be a rechargeable battery (e.g., lead-based, nickel-based,lithium-ion based, etc.). It is also envisioned that the power source400 includes at least one disposable battery. The disposable battery maybe between about 9 volts and about 30 volts.

The power source 400 includes one or more battery cells 401 depending onthe current load needs of the instrument 10. Further, the power source400 includes one or more ultracapacitors 402 which act as supplementalpower storage due to their much higher energy density than conventionalcapacitors. Ultracapacitors 402 can be used in conjunction with thecells 401 during high energy draw. The ultracapacitors 402 can be usedfor a burst of power when energy is desired/required more quickly thancan be provided solely by the cells 401 (e.g., when clamping thicktissue, rapid firing, clamping, etc.), as cells 401 are typicallyslow-drain devices from which current cannot be quickly drawn. Thisconfiguration can reduce the current load on the cells thereby reducingthe number of cells 401. It is envisioned that cells 401 can beconnected to the ultracapacitors 402 to charge the capacitors.

The power source 400 may be removable along with the drive motor 200 toprovide for recycling of these components and reuse of the instrument10. In another embodiment, the power source 400 may be an externalbattery pack which is worn on a belt and/or harness by the user andwired to the instrument 10 during use.

The power source 400 is enclosed within an insulating shield 404 whichmay be formed from an absorbent, flame resistant and retardant material.The shield 404 prevents heat generated by the power source 400 fromheating other components of the instrument 10. In addition, the shield404 may also be configured to absorb any chemicals or fluids which mayleak from the cells 402 during heavy use and/or damage.

The power source 400 is coupled to a power adapter 406 which isconfigured to connect to an external power source (e.g., DCtransformer). The external power source may be used to recharge thepower source 400 or provide for additional power requirements. The poweradapter 406 may also be configured to interface with electrosurgicalgenerators which can then supply power to the instrument 10. In thisconfiguration, the instrument 10 also includes an AC-to-DC power sourcewhich converts RF energy from the electrosurgical generators and powersthe instrument 10.

In another embodiment the power source 400 is recharged using aninductive charging interface. The power source 400 is coupled to aninductive coil (not explicitly shown) disposed within the proximalportion of the housing 110. Upon being placed within an electromagneticfield, the inductive coil converts the energy into electrical currentthat is then used to charge the power source 400. The electromagneticfield may be produced by a base station (not explicitly shown) which isconfigured to interface with the proximal portion of the housing 110,such that the inductive coil is enveloped by the electromagnetic field.This configuration eliminates the need for external contacts and allowsfor the proximal portion of the housing 110 to seal the power source 400and the inductive coil within a water-proof environment which preventsexposure to fluids and contamination.

With reference to FIG. 5, the instrument 10 also includes one or moresafety circuits such as a discharge circuit 410 and a motor and batteryoperating module 412. For clarity, wires and other circuit elementsinterconnecting various electronic components of the instrument 10 arenot shown, but such electromechanical connections wires are contemplatedby the present disclosure. Certain components of the instrument 10communicate wirelessly.

The discharge circuit 410 is coupled to a switch 414 and a resistiveload 417 which are in turn coupled to the power source 400. The switch414 may be a user activated or an automatic (e.g., timer, counter)switch which is activated when the power source 400 needs to be fullydischarged for a safe and low temperature disposal (e.g., at the end ofsurgical procedure). Once the switch 414 is activated, the load 417 iselectrically connected to the power source 400 such that the potentialof the power source 400 is directed to the load 417. The automaticswitch may be a timer or a counter which is automatically activatedafter a predetermined operational time period or number of uses todischarge the power source 400. The load 417 has a predeterminedresistance sufficient to fully and safely discharge all of the cells401.

The motor and battery operating module 412 is coupled to one or morethermal sensors 413 which determine the temperature within the drivemotor 200 and the power source 400 to ensure safe operation of theinstrument 10. The sensors may be an ammeter for determining the currentdraw within the power source 400, a thermistor, a thermopile, athermocouple, a thermal infrared sensor and the like. Monitoringtemperature of these components allows for a determination of the loadbeing placed thereon. The increase in the current flowing through thesecomponents causes an increase in temperature therein. The temperatureand/or current draw data may then be used to control the powerconsumption in an efficient manner or assure safe levels of operation.

In order to ensure safe and reliable operation of the instrument 10, itis desirable to ensure that the power source 400 is authentic and/orvalid (e.g., conforms to strict quality and safety standards) andoperating within a predetermined temperature range. Authentication thatthe power source 400 is valid minimizes risk of injury to the patientand/or the user due to poor quality.

With reference to FIG. 9, the power source 400 is shown having one ormore battery cells 401, a temperature sensor 403 and an embeddedmicrocontroller 405 coupled thereto. The microcontroller 405 is coupledthrough wired and/or wireless communication protocols to microcontroller500 (FIG. 14) of the instrument 10 to authenticate the power source 400.In one embodiment, the temperature sensor 403 can be coupled directly tothe microcontroller 500 instead of being coupled to the embeddedmicrocontroller 405. The temperature sensor 403 may be a thermistor, athermopile, a thermocouple, a thermal infrared sensor, a resistancetemperature detector, linear active thermistor, temperature-responsivecolor changing strips, bimetallic contact switches, and the like. Thetemperature sensor 403 reports the measured temperature to themicrocontroller 405 and/or microcontroller 500.

The embedded microcontroller 405 executes a so-called challenge-responseauthentication algorithm with the microcontroller 500 which isillustrated in FIG. 10. In step 630, the power source 400 is connectedto the instrument 10 and the instrument 10 is switched on. Themicrocontroller 500 sends a challenge request to the embeddedmicrocontroller 405. In step 632, the microcontroller 405 interprets thechallenge request and generates a response as a reply to the request.The response may include an identifier, such as a unique serial numberstored in a radio frequency identification tag or in memory of themicrocontroller 405, or a unique electrical measurable value of thepower source 400 (e.g., resistance, capacitance, inductance, etc.). Inaddition, the response includes the temperature measured by thetemperature sensor 403.

In step 634, the microcontroller 500 decodes the response to obtain theidentifier and the measured temperature. In step 636, themicrocontroller 500 determines if the power source 400 is authenticbased on the identifier, by comparing the identifier against apre-approved list of authentic identifiers. If the identifier is notvalid, the instrument 10 is not going to operate and displays a “failureto authenticate battery” message via the user interface 120. If theidentifier is valid, the process proceeds to step 640 where the measuredtemperature is analyzed to determine if the measurement is within apredetermined operating range. If the temperature is outside the limit,the instrument 10 also displays the failure message. Thus, if thetemperature is within the predetermined limit and the identifier isvalid, in step 642, the instrument commences operation, which mayinclude providing a “battery authenticated” message to the user.

Referring back to FIGS. 4 and 5 a plurality of sensors for providingfeedback information relating to the function of the instrument 10 areillustrated. Any combination of sensors may be disposed within theinstrument 10 to determine its operating stage, such as, staplecartridge load detection as well as status thereof, articulation,clamping, rotation, stapling, cutting and retracting, and the like. Thesensors can be actuated by proximity, displacement or contact of variousinternal components of the instrument 10 (e.g., firing rod 220, drivemotor 200, etc.).

In the illustrated embodiments, the sensors can be rheostats (e.g.,variable resistance devices), current monitors, conductive sensors,capacitive sensors, inductive sensors, thermal-based sensors, limitactuated switches, multiple position switch circuits, pressuretransducers, linear and/or rotary variable displacement transducers,linear and/or rotary potentiometers, optical encoders, ferromagneticsensors, Hall Effect sensors, and/or proximity switches. The sensorsmeasure rotation, velocity, acceleration, deceleration, linear and/orangular displacement, detection of mechanical limits (e.g., stops), etc.This is attained by implementing multiple indicators arranged in eitherlinear or rotational arrays on the mechanical drive components of theinstrument 10. The sensors then transmit the measurements to themicrocontroller 500 which determines the operating status of theinstrument 10. In addition, the microcontroller 500 also adjusts themotor speed or torque of the instrument 10 based on the measuredfeedback.

In embodiments where the clutch 300 is implemented as a slip clutch asshown in FIG. 11, linear displacement sensors (e.g., linear displacementsensor 237) are positioned distally of the clutch 300 to provideaccurate measurements. In this configuration, slippage of the clutch 300does not affect the position, velocity and acceleration measurementsrecorded by the sensors.

With reference to FIG. 4, a load switch 230 is disposed within thearticulation housing 172. The switch 230 is connected in series with theswitch 114, preventing activation of the instrument 10 unless theloading unit 169 is properly loaded into the instrument 10. If theloading unit 169 is not loaded into the instrument 10, the main powerswitch (e.g., switch 114) is open, thereby preventing use of anyelectronic or electric components of the instrument 10. This alsoprevents any possible current draw from the power source 400 allowingthe power source 400 to maintain a maximum potential over its specifiedshelf life.

Thus, the switch 230 acts as a so-called “lock-out” switch whichprevents false activation of the instrument 10 since the switch isinaccessible to external manipulation and can only be activated by theinsertion of the loading unit 169. The switch 230 is activated bydisplacement of a plunger or sensor tube as the loading unit 169 isinserted into the endoscopic portion 140. Once the switch 230 isactivated, the power from the power source 400 is supplied to theelectronic components (e.g., sensors, microcontroller 500, etc.) of theinstrument 10 providing the user with access to the user interface 120and other inputs/outputs. This also activates the visual outputs 123 tolight up according to the light combination indicative of a properlyloaded loading unit 169 wherein all the lights are off as described inTable 1.

More specifically, as shown in FIGS. 18 and 19, the endoscopic portion140 includes a sensor plate 360 therein which is in mechanical contactwith a sensor tube also disposed within the endoscopic portion 140 andaround the distal portion 224 of firing rod 220. The distal portion 224of the firing rod 220 passes through an opening 368 at a distal end of asensor cap 364. The sensor cap 364 includes a spring and abuts theswitch 230. This allows the sensor cap 364 to be biased against thesensor tube 362 which rests on the distal end of the sensor cap 364without passing through the opening 368. Biasing of the sensor tube 362then pushes out the sensor plate 360 accordingly.

When the loading unit 169 is loaded into the endoscopic portion 140, theproximal portion 171 abuts the sensor plate 360 and displaces the plate360 in a proximal direction. The sensor plate 360 then pushes the sensortube 362 in the proximal direction which then applies pressure on thesensor cap 364 thereby compressing the spring 366 and activating theswitch 230 denoting that the loading unit 169 has been properlyinserted.

Once the loading unit 169 is inserted into the endoscopic portion, theswitch 230 also determines whether the loading unit 169 is loadedcorrectly based on the position thereof. If the loading unit 169 isimproperly loaded, the switch 114 is not activated and an error code isrelayed to the user via the user interface 120 (e.g., all the lights areoff as described in Table 1). If the loading unit 169 has already beenfired, any mechanical lockouts have been previously activated or thestaple cartridge has been used, the instrument 10 relays the error viathe user interface 120, e.g., the first light 123 a is flashing.

In one embodiment, a second lock-out switch 259 (FIG. 4) coupled to themain switch 114 may be implemented in the instrument 10 as abioimpedance, capacitance or pressure sensor disposed on the top surfaceof the handle portion 112 configured to be activated when the usergrasps the instrument 10. Thus, unless the instrument 10 is graspedproperly, the operation of the switch 114 is disabled.

With reference to FIG. 6, the instrument 10 includes a positioncalculator 416 for determining and outputting current linear position ofthe firing rod 220. The position calculator 416 is electricallyconnected to a linear displacement sensor 237 and a rotation speeddetecting apparatus 418 is coupled to the drive motor 200. The apparatus418 includes an encoder 420 coupled to the motor for producing two ormore encoder pulse signals in response to the rotation of the drivemotor 200. The encoder 420 transmits the pulse signals to the apparatus418 which then determines the rotational speed of the drive motor 200.The position calculator 416 thereafter determines the linear speed andposition of the firing rod based on the rotational speed of the drivemotor 200 since the rotation speed is directly proportional to thelinear speed of the firing rod 220. The position calculator 416 and thespeed calculator 422 are coupled to the microcontroller 500 whichcontrols the drive motor 200 in response to the sensed feedback form thecalculators 416 and 422. This configuration is discussed in more detailbelow with respect to FIG. 14.

The instrument 10 includes first and second indicators 320 a, 320 bdisposed on the firing rod 220, which determine the speed of firing rod220 and the location of firing rod 220 with respect to drive tube 210and/or housing 110. For instance, a limit switch may be activated (e.g.,shaft start position sensor 239 and clamp position sensor 232) bysensing first and second indicators 320 a and/or 320 b (e.g., bumps,grooves, indentations, etc.) passing thereby to determine position offiring rod 220, speed of firing rod 220 and mode of the instrument 10(e.g., clamping, grasping, firing, sealing, cutting, retracting).Further, the feedback received from first and second indicators 320 a,320 b may be used to determine when firing rod 220 should stop its axialmovement (e.g., when drive motor 200 should cease) depending on the sizeof the particular loading unit attached thereto.

More specifically, as the firing rod 220 is moved in the distaldirection from its resting (e.g., initial) position, the first actuationof the position sensor 231 is activated by the first indicator 320 awhich denotes that operation of the instrument 10 has commenced. As theoperation continues, the firing rod 220 is moved further distally toinitiate clamping, which moves first indicator 320 a to interface withclamp position sensor 232. Further advancement of the firing rod 220moves the second indicator 320 b to interface with the position sensor232 which indicates that the instrument 10 has been fired.

As discussed above, the position calculator 416 is coupled to a lineardisplacement sensor 237 disposed adjacent to the firing rod 220. In oneembodiment, the linear displacement sensor 237 may be a magnetic sensor.The firing rod 220 may be magnetized or may include magnetic materialtherein. The magnetic sensor may be a ferromagnetic sensor or a HallEffect sensor which is configured to detect changes in a magnetic field.As the firing rod 220 is translated linearly due to the rotation of thedrive motor 200, the change in the magnetic field in response to thetranslation motion is registered by the magnetic sensor. The magneticsensor transmits data relating to the changes in the magnetic field tothe position calculator 416 which then determines the position of thefiring rod 220 as a function of the magnetic field data.

In one embodiment, a select portion of the firing rod 220 may bemagnetized, such as the threads of the internally-threaded portion 212or other notches (e.g., indicators 320 a and/or 320 b) disposed on thefiring rod 220 may include or be made from a magnetic material. Thisallows for correlation of the cyclical variations in the magnetic fieldwith each discrete translation of the threads as the magnetized portionsof the firing rod 220 are linearly translated. The position calculator416 thereafter determines the distance and the position of the firingrod 220 by summing the number of cyclical changes in the magnetic fieldand multiplies the sum by a predetermined distance between the threadsand/or notches.

In one embodiment, the linear displacement sensor 237 may be apotentiometer or a rheostat. The firing rod 220 includes a contact(e.g., wiper terminal) disposed in electromechanical contact with thelinear displacement sensor 237. The contact slides along the surface ofthe linear displacement sensor 237 as the firing rod 220 is moved in thedistal direction by the drive motor 200. As the contact slides acrossthe potentiometer and/or the rheostat, the voltage of the potentiometerand the resistance of the rheostat vary accordingly. Thus, the variationin voltage and resistance is transmitted to the position calculator 416which then extrapolates the distance traveled by the firing rod 220and/or the firing rod coupling 190 and the position thereof.

In one embodiment, the position calculator 416 is coupled to one or moreswitches 421 which are actuated by the threads of theinternally-threaded portion 212 or the indicators 320 a and/or 320 b asthe firing rod 220 and the firing rod coupling 190 are moved in thedistal direction. The position calculator 416 counts the number ofthreads which activated the switch 421 and then multiplies the number bya predetermined distance between the threads or the indicators 320 aand/or 320 b.

The instrument 10 also includes a speed calculator 422 which determinesthe current speed of a linearly moving firing rod 220 and/or the torquebeing provided by the drive motor 200. The speed calculator 422 isconnected to the linear displacement sensor 237 which allows the speedcalculator 422 to determine the speed of the firing rod 220 based on therate of change of the displacement thereof.

The speed calculator 422 is coupled to the rotation speed detectingapparatus 424 which includes the encoder 426. The encoder 426 transmitsthe pulses correlating to the rotation of the drive motor 200 which thespeed calculator 422 then uses to calculate the linear speed of thefiring rod 220. In another embodiment, the speed calculator 422 iscoupled to a rotational sensor 239 which detects the rotation of thedrive tube 210, thus, measuring the rate of rotation of the drive tube210 which allows for determination of the linear velocity of the firingrod 220.

The speed calculator 422 is also coupled to a voltage sensor 428 whichmeasures the back electromotive force (“EMF”) induced in the drive motor200. The back EMF voltage of the drive motor 200 is directlyproportional to the rotational speed of the drive motor 200 which, asdiscussed above, is used to determine the linear speed of the firing rod220.

Monitoring of the speed of the drive motor 200 can also be accomplishedby measuring the voltage across the terminals thereof under constantcurrent conditions. An increase in a load of the drive motor 200 yieldsa decrease in the voltage applied at the motor terminals, which isdirectly related to the decrease in the speed of the motor. Thus,measuring the voltage across the drive motor 200 provides fordetermining the load being placed thereon. In addition, by monitoringthe change of the voltage over time (dV/dt), the microprocessor 500 candetect a quick drop in voltage which correlates to a large change in theload or an increase in temperature of the drive motor 200 and/or thepower source 400.

In a further embodiment, the speed calculator 422 is coupled to acurrent sensor 430 (e.g., an ammeter). The current sensor 430 is inelectrical communication with a shunt resistor 432 which is coupled tothe drive motor 200. The current sensor 430 measures the current beingdrawn by the drive motor 200 by measuring the voltage drop across theresistor 432. Since the current used to power the drive motor 200 isproportional to the rotational speed of the drive motor 200 and, hence,the linear speed of the firing rod 220, the speed calculator 422determines the speed of the firing rod 220 based on the current draw ofthe drive motor 200.

The speed calculator 422 may also be coupled to a second voltage sensor(not explicitly shown) for determining the voltage within the powersource 400 thereby calculating the power draw directly from the source.In addition, the change in current over time (dI/dt) can be monitored todetect quick spikes in the measurements which correspond to a largeincrease in applied torque by the drive motor 200. Thus, the currentsensor 430 is used to determine the speed and the load of the drivemotor 200.

In addition, the velocity of the firing rod 220 as measured by the speedcalculator 422 may be then compared to the current draw of the drivemotor 200 to determine whether the drive motor 200 is operatingproperly. Namely, if the current draw is not commensurate (e.g., large)with the velocity (e.g., low) of the firing rod 220 then the motor 200is malfunctioning (e.g., locked, stalled, etc.). If a stall situation isdetected, or the current draw exceeds predetermined limits, the positioncalculator 416 then determines whether the firing rod 220 is at amechanical stop. If this is the case, then the microcontroller 500 canshut down the drive motor 200 or enters a pulse and/or pause mode (e.g.,discontinuous supply of power to the drive motor 200) to unlock theinstrument 10 and retract the firing rod 220.

In one embodiment, the speed calculator 422 compares the rotation speedof the drive tube 210 as detected by the rotation sensor 239 and that ofthe drive motor 200 based on the measurements from and the rotationspeed detecting apparatus 424. This comparison allows the speedcalculator 422 to determine whether there is a clutch activation problem(e.g., slippage) if there is a discrepancy between the rotation of theclutch 300 and that of the drive tube 210. If slippage is detected, theposition calculator 416 then determines whether the firing rod 220 is ata mechanical stop. If this is the case, then the microcontroller 500 canshut down the instrument 10 or enter a pulse and/or pause mode (e.g.,discontinuous supply of power to the drive motor 200), or retract thefiring rod 220.

In addition to linear and/or rotational displacement of the firing rod220 and other drive components, the instrument 10 also includes sensorsadapted to detect articulation of the end effector 160. With referenceto FIG. 4, the instrument 10 includes a rotation sensor 241 adapted toindicate the start position, the rotational direction and the angulardisplacement of the rotating housing assembly 180 at the start of theprocedure as detected by the shaft start position sensor 231. Therotation sensor 241 operates by counting the number of indicatorsdisposed on the inner surface of the rotation knob 182 as the rotationknob 182 is rotated. The count is then transmitted to themicrocontroller 500 which then determines the rotational position of theendoscopic portion 142. This can be communicated wirelessly or throughan electrical connection on the endoscopic portion and wires to themicrocontroller 500.

The instrument 10 also includes an articulation sensor 235 whichdetermines articulation of the end effector 160. The articulation sensor235 counts the number of teeth 263 disposed on the articulation gear 233by which the articulation knob 176 has been rotated from its 0°position, namely the center position of the articulation knob 176 and,hence, of the end effector 160 as shown in FIG. C. The 0° position andcan be designated by a central unique indicator 265 also disposed on thearticulation gear 233 which corresponds with the first position of theend effector 160, where longitudinal axis B-B is substantially alignedwith longitudinal axis A-A. The count is then transmitted to themicrocontroller 500 which then determines the articulation position ofthe end effector 160 and reports the articulation angle via theinterface 120.

In addition, the articulation angle can be used for the so-called “autostop” mode. During this operational mode, the instrument 10automatically stops the articulation of the end effector 160 when theend effector 160 is at its central first position. Namely, as the endeffector 160 is articulated from a position in which longitudinal axisB-B is disposed at an angle to longitudinal axis A-A towards the firstposition, the articulation is stopped when the longitudinal axis B-B issubstantially aligned with longitudinal axis A-A. This position isdetected by the articulation sensor 235 based on the central indicator.This mode allows the endoscopic portion 140 to be extracted without theuser having to manually align the end effector 160.

With reference to FIG. 1, the present disclosure provides a loading unitidentification system 440 which allows the instrument 10 to identify theloading unit 169 and to determine operational status thereof. Theidentification system 440 provides information to the instrument 10 onstaple size, cartridge length, type of the loading unit 169, status ofcartridge, proper engagement, and the like. This information allows theinstrument to adjust clamping forces, speed of clamping, and firing andend of stroke for various length staple cartridges.

The loading unit identification system 440 may also be adapted todetermine and communicate to the instrument 10 (e.g., a control system501 shown in FIG. 14) various information, including the speed, power,torque, clamping, travel length, and/or strength limitations foroperating the particular end effector 160. The control system 501 mayalso determine the operational mode and adjust the voltage, clutchspring loading, and/or stop points for travel of the components. Morespecifically, the identification system may include a component (e.g., amicrochip, emitter or transmitter) disposed in the end effector 160 thatcommunicates (e.g., wirelessly, via infrared signals, etc.) with thecontrol system 501, or a receiver therein. It is also envisioned that asignal may be sent via firing rod 220, such that firing rod 220functions as a conduit for communications between the control system 501and end effector 160. In another embodiment, the signals can be sentthrough an intermediate interface, such as a feedback controller 603(FIGS. 15-17).

By way of example, the sensors discussed above may be used to determineif the staples 66 have been fired from the staple cartridge, whetherthey have been fully fired, whether and the extent to which the beam hasbeen retracted proximally through the staple cartridge, and otherinformation regarding the operation of the loading unit. In certainembodiments of the present disclosure, the loading unit incorporatescomponents for identifying the type of loading unit, and/or staplecartridge loaded on the instrument 10, including infra red, cellular, orradio frequency identification chips. The type of loading unit and/orstaple cartridge may be received by an associated receiver within thecontrol system 501, or an external device in the operating room forproviding feedback, control and/or inventory analysis.

Information can be transmitted to the instrument 10 via a variety ofcommunication protocols (e.g., wired or wireless) between the loadingunit 169 and the instrument 10. The information can be stored within theloading unit 169 in a microcontroller, microprocessor, non-volatilememory, radio frequency identification tags, and/or identifiers ofvarious types such as optical, color, displacement, magnetic,electrical, binary and/or gray coding (e.g., conductance, resistance,capacitance, impedance).

In one embodiment, the loading unit 169 and the instrument 10 includecorresponding wireless transceivers, an identifier 442, and aninterrogator 444. The identifier 442 includes memory or may be coupledto a microcontroller for storing various identification and statusinformation regarding the loading unit 169. Once the loading unit 169 iscoupled to the instrument 10, the instrument 10 interrogates theidentifier 442 via the interrogator 444 for an identifying code. Inresponse to the interrogatory, the identifier 442 replies with theidentifying code corresponding to the loading unit 169. Duringoperation, once identification has occurred, the identifier 442 isconfigured to provide the instrument 10 with updates as to the status ofthe loading unit 169 (e.g., mechanical and/or electrical malfunction,position, articulation, etc.).

The identifier 442 and the interrogator 444 are configured tocommunicate with each other using one or more of the followingcommunication protocols such as Bluetooth®, ANT3®, KNX®, ZWave®, X10®Wireless USB®, IrDA®, Nanonet®, Tiny OS®, ZigBee®, 802.11 IEEE, and/orother radio, infrared, UHF, VHF communications and the like. In oneembodiment, the transceiver 400 may be a radio frequency identification(RFID) tag, either active or passive, depending on the interrogatorcapabilities of the transceiver 402.

FIGS. 15A and B illustrate additional embodiments of the loading unit169 having various types of identification devices. With reference toFIG. 15A, a proximal end 171 of the loading unit 169 having anelectrical identifier 173 is shown. The identifier 173 may include oneor more resistors, capacitors, and/or inductors and is coupled with acorresponding electrical contact 181 disposed on the distal end of theendoscopic portion 140. The contact may include slip rings, brushesand/or fixed contacts disposed in the endoscopic portion. The identifier173 may be disposed on any location of the loading unit 168 and may beformed on a flexible or fixed circuit or may be traced directly on thesurface of the loading unit 169.

When the loading unit 169 is coupled with the endoscopic portion 140,the contact applies a small current through the electrical identifier173. The interrogator contact also includes a corresponding electricalsensor which measures the resistance, impedance, capacitance, and/orimpedance of the identifier 173. The identifier 173 has a uniqueelectrical property (e.g., resistance, capacitance, inductance, etc.)which corresponds to the identifying code of the loading unit 169, thus,when the electrical property thereof is determined, the instrument 10determines the identity of the loading unit 169 based on the measuredproperty.

In one embodiment, the identifier 173 may be a magnetic identifier suchas gray coded magnets and/or ferrous nodes incorporating predeterminedunique magnetic patterns identifying the loading unit 169 by theidentifying code. The magnetic identifier is read via a magnetic sensor(e.g., ferromagnetic sensor, Hall Effect sensor, etc.) disposed at thedistal end of the endoscopic portion 140. The magnetic sensor transmitsthe magnetic data to the instrument 10 which then determines theidentity of the loading unit 169.

FIG. 15B illustrates the proximal end 171 of the loading unit 169 havingone or more protrusions 175. The protrusions 175 can be of any shape,such as divots, bumps, strips, etc., of various dimensions. Theprotrusions 175 interface with corresponding displacement sensors 183disposed within the proximal segment of the endoscopic portion 140. Thesensors are displaced when the protrusions 175 are inserted into theendoscopic portion. The amount of the displacement is analyzed by thesensors and converted into identification data, allowing the instrument10 to determine staple size, cartridge length, type of the loading unit169, proper engagement, and the like. The displacement sensors can beswitches, contacts, magnetic sensors, optical sensors, variableresistors, or linear and rotary variable displacement transducers whichcan be spring loaded. The switches are configured to transmit binarycode to the instrument 10 based on their activation status. Morespecifically, some protrusions 175 extend a distance sufficient toselectively activate some of the switches, thereby generating a uniquecode based on the combination of the protrusions 175.

In another embodiment, the protrusion 175 can be color coded. Thedisplacement sensors 183 include a color sensor configured to determinethe color of the protrusion 175 to measure one or more properties of theloading unit 169 based on the color and transmits the information to theinstrument 10.

FIG. 16 shows a method for identifying the loading unit 169 andproviding status information concerning the loading unit 169 to theinstrument 10. In step 650 it is determined whether the loading unit 169is properly loaded into the instrument 10. This may be determined bydetecting whether contact has been made with the identifier 173 and/orprotrusions 175. If the loading unit 169 is properly loaded, in step652, the loading unit 169 communicates to the instrument 10 a readystatus (e.g., turning on the first light of the visual outputs 123).

In 654, the instrument 10 verifies whether the loading unit 169 has beenpreviously fired. The identifier 442 stores a value indicative of thepreviously fired status. If the loading unit 169 was fired, in step 656,the instrument 10 provides an error response (e.g., flashing the firstlight of the visual outputs 123). If the loading unit 169 has not beenfired, in step 658 the loading unit 169 provides identification andstatus information (e.g., first light is turned on) to the instrument 10via the identification system 440. The determination whether the loadingunit 169 has been fired is made based on the saved “previously fired”signal saved in the memory of the identifier 442 as discussed in moredetail below with respect to step 664. In step 660, the instrument 10adjusts its operating parameters in response to the information receivedfrom the loading unit 169.

The user performs a surgical procedure via the instrument 10 in step662. Once the procedure is complete and the loading unit 169 has beenfired, the instrument 10 transmits a “previously fired” signal to theloading unit 169. In step 664, the loading unit 169 saves the“previously fired” signal in the memory of the identifier 442 for futureinterrogations by the instrument 10 as discussed with respect to step654.

With reference to FIG. 17, the loading unit 169 includes one or moretissue sensors disposed within the end effector 160 for detecting thetype of object being grasped, such recognizing non-tissue objects andthe tissue type of the object. The sensors are also configured todetermine amount of blood flow being passed between the jaw members ofthe end effector 160. More specifically, a first tissue sensor 177 isdisposed at a distal portion of the anvil assembly 162 and a secondtissue sensor 179 is disposed at a distal portion of the cartridgeassembly 164. The sensors 177 and 179 are coupled to the identifier 442allowing for transmission of sensor data to the microcontroller 500 ofthe instrument 10.

The sensors 177 and 179 are adapted to generate a field and/or waves inone or more arrays or frequencies therebetween. The sensors 177 and 179may be acoustic, ultrasonic, ferromagnetic, Hall Effect sensors, laser,infrared, radio frequency, or piezoelectric devices. The sensors 177 and179 are calibrated for ignoring commonly occurring material, such asair, bodily fluids and various types of human tissue and for detectingcertain types of foreign matter. The foreign matter may be bone,tendons, cartilage, nerves, major arteries and non-tissue matter, suchas ceramic, metal, plastic, etc.

The sensors 177 and 179 detect the foreign matter passing between theanvil and cartridge assemblies 162 and 164 based on the absorption,reflection and/or filtering of the field signals generated by thesensors. If the material reduces or reflects a signal, such that thematerial is outside the calibration range and is, therefore, foreign,the sensors 177 and 179 transmit the interference information to themicrocontroller 500 which then determines the type of the material beinggrasped by the end effector 160. The determination may be made bycomparing the interference signals with a look up table listing varioustypes of materials and their associated interference ranges. Themicrocontroller 500 then alerts the user of the foreign material beinggrasped as well as the identity thereof. This allows the user to preventclamping, cutting or stapling through areas containing foreign matter.

FIG. 20 illustrates a control system 501 including the microcontroller500 which is coupled to the position and speed calculators 416 and 422,the loading unit identification system 440, the user interface 120, thedrive motor 200, and a data storage module 502. In addition themicrocontroller 500 may be directly coupled to various sensors (e.g.,first and second tissue sensors 177 and 179, the load switch 230, shaftstart position sensor 231, clamp position sensor 232, articulationsensor 235, linear displacement sensor 237, rotational sensor 239,firing rod rotation sensor 241, motor and battery operating module 412,rotation speed detecting apparatus 418, switches 421, voltage sensor428, current sensor 430, the interrogator 444, etc.).

The microcontroller 500 includes internal memory which stores one ormore software applications (e.g., firmware) for controlling theoperation and functionality of the instrument 10. The microcontroller500 processes input data from the user interface 120 and adjusts theoperation of the instrument 10 in response to the inputs. Theadjustments to the instrument 10 may including powering the instrument10 on or off, speed control by means of voltage regulation or voltagepulse width modulation, torque limitation by reducing duty cycle orpulsing the voltage on and off to limit average current delivery duringa predetermined period of time.

The microcontroller 500 is coupled to the user interface 120 via a userfeedback module 504 which is configured to inform the user ofoperational parameters of the instrument 10. The user feedback module504 instructs the user interface 120 to output operational data on thescreen 122. In particular, the outputs from the sensors are transmittedto the microcontroller 500 which then sends feedback to the userinstructing the user to select a specific mode, speed or function forthe instrument 10 in response thereto.

The loading unit identification system 440 instructs the microcontroller500 which end effector is on the loading unit. In an embodiment, thecontrol system 501 is capable of storing information relating to theforce applied to firing rod 220 and/or end effector 160, such that whenthe loading unit 169 is identified, the microcontroller 500automatically selects the operating parameters for the instrument 10.This allows for control of the force being applied to the firing rod 220so that firing rod 220 can drive the particular end effector 160 that ison the loading unit in use at the time.

The microcontroller 500 also analyzes the calculations from the positionand speed calculators 416 and 422 and other sensors to determine theactual position and/or speed of the firing rod 220 and operating statusof components of the instrument 10. The analysis may includeinterpretation of the sensed feedback signal from the calculators 416and 422 to control the movement of the firing rod 220 and othercomponents of the instrument 10 in response to the sensed signal. Themicrocontroller 500 is configured to limit the travel of the firing rod220 once the firing rod 220 has moved beyond a predetermined point asreported by the position calculator 416. Additional parameters which maybe used by the microcontroller 500 to control the instrument 10 includemotor and/or battery temperature, number of cycles remaining and used,remaining battery life, tissue thickness, current status of the endeffector, transmission and reception, external device connection status,etc.

In one embodiment, the instrument 10 includes various sensors configuredto measure current (e.g., ammeter), voltage (e.g., voltmeter), proximity(e.g., optical sensors), temperature (e.g., thermocouples, thermistors,etc.), and/or force (e.g., strain gauges, load cells, etc.) to determinefor loading conditions on the loading unit 169. During operation of theinstrument 10 it is desirable to know the forces being exerted by theinstrument 10 on the target tissue during the approximation process andduring the firing process. Detection of abnormal loads (e.g., outside apredetermined load range) indicates a problem with the instrument 10and/or clamped tissue which is communicated to the user.

Monitoring of load conditions may be performed by one or more of thefollowing methods: monitoring speed of the drive motor 200, monitoringtorque being applied by the motor, proximity of jaw members 162 and 164,monitoring temperature of components of the instrument 10, and/ormeasuring the load on the firing rod 220 via a strain sensor 185 (FIG.6) and/or other load bearing components of the instrument 10. Speed andtorque monitoring is discussed above with respect to FIG. 5 and thespeed calculator 422.

In an embodiment, the drive motor 200 is coupled to a motor drivercircuit (not shown) which controls the operation of the drive motor 200including the flow of electrical energy from the power source 400 to thedrive motor 200. The motor driver circuit includes a plurality ofsensors configured to measure an operational state of the drive motor200 and the power source 400. The sensors may include voltage sensors,current sensors, temperature sensors, telemetry sensors, opticalsensors, or combinations thereof. The sensors may measure voltage,current, and/or other electrical properties of the electrical energysupplied by the power source 400. The sensors may also measurerotational speed as revolutions per minute (RPM), torque, temperature,current draw, and/or other properties of the drive motor 200. Thesensors can be indicative of load conditions on the end effector 160and/or the instrument 10. In particular, the sensors can be correlatedwith the force required to fire or drive the staples 66 through tissue.RPM may be determined by measuring the rotation of the drive motor 200.Position of various drive shafts may be determined by using variouslinear sensors disposed in or in proximity to the shafts or extrapolatedfrom the RPM measurements. In embodiments, torque may be calculatedbased on the regulated current draw of the drive motor 200 at a constantRPM.

Measuring the distance between the jaw members 162 and 164 can also beindicative of load conditions on the end effector 160 and/or theinstrument 10. When large amounts of force are imparted on the jawmembers 162 and 164, the jaw members are deflected outwards. The jawmembers 162 and 164 are parallel to each other during normal operation,however, during deformation, the jaw members are at an angle relative toeach other. Thus, measuring the angle between the jaw members 162 and164 allows for a determination of the deformation of the jaw members dueto the load being exerted thereon. The jaw members may include straingauges 187 and 189 as shown in FIG. 17 to directly measure the loadbeing exerted thereon. Alternatively, one or more proximity sensors 191and 193 can be disposed at the distal tips of the jaw members 162 and164 to measure the angle therebetween. These measurements are thentransmitted to the microcontroller 500 which analyzes the angle and/orstrain measurements and alerts the user of the stress on the endeffector 160.

In another embodiment, the firing rod 220 or other load-bearingcomponents include one or more strain gauges and/or load sensorsdisposed thereon. Under high strain conditions, the pressure exerted onthe instrument 10 and/or the end effector 160 is translated to thefiring rod 220 causing the firing rod 220 to deflect, leading toincreased strain thereon. The strain gauges then report the stressmeasurements to the microcontroller 500. In another embodiment, aposition, strain or force sensor may be disposed on the clutch plate302.

During the approximation process, as the end effector 160 is clampedabout tissue, the sensors disposed in the instrument 10 and/or the endeffector 160 indicate to the microprocessor 500 that the end effector160 is deployed about abnormal tissue (e.g., low or high loadconditions). Low load conditions are indicative of a small amount oftissue being grasped by the end effector 160. High load conditionsdenote that too much tissue and/or a foreign object (e.g., tube, stapleline, clips, etc.) is being grasped. In addition, a high load conditionmay denote that abnormal tissue (e.g., bowel) for cutting is beinggrasped. The microprocessor 500 thereafter indicates to the user via theuser interface 120 that a more appropriate loading unit 169 and/orinstrument 10 should be chosen. In addition, the microprocessor 500 mayindicate to the user via the user interface 120 that abnormal tissue isbeing grasped by the end effector 160.

During the firing process, the sensors can alert the user of a varietyof errors. Sensors may communicate to the microcontroller 500 that astaple cartridge or a portion of the instrument 10 is faulty. Inaddition, the sensors can detect sudden spikes in the force exerted onthe knife, which is indicative of encountering a foreign body.Monitoring of force spikes could also be used to detect the end of thefiring stroke, such as when the firing rod 220 encounters the end of thestapling cartridge and runs into a hard stop. This hard stop creates aforce spike which is relatively larger than those observed during normaloperation of the instrument 10 and could be used to indicate to themicrocontroller that the firing rod 220 has reached the end of loadingunit 169. Measuring of the force spikes can be combined with positionalfeedback measurements (e.g., from an encoder, linear variabledisplacement transducer, linear potentiometer, etc.) as discussed withrespect to position and speed calculators 416 and 422. This allows foruse of various types of staple cartridges (e.g., multiple lengths) withthe instrument 10 without modifying the end effector 160.

When force spikes are encountered, the instrument 10 notifies the userof the condition and takes preventative measures by entering a so-called“pulse” or an electronic clutching mode, which is discussed in moredetail below. During this mode the drive motor 200 is controlled to runonly in short bursts to allow for the pressure between the graspedtissue and the end effector 160 to equalize. The electronic clutchinglimits the torque exerted by the drive motor 200 and prevents situationswhere high amounts of current are drawn from the power source 400. This,in turn, prevents damage to electronic and mechanical components due tooverheating which accompanies overloading and high current drawsituations.

The microcontroller 500 controls the drive motor 200 through a motordriver via a pulse width modulated control signal. The motor driver isconfigured to adjust the speed of the drive motor 200 either inclockwise or counter-clockwise direction. The motor driver is alsoconfigured to switch between a plurality of operational modes whichinclude an electronic motor braking mode, a constant speed mode, anelectronic clutching mode, and/or a controlled current activation mode.In electronic braking mode, two terminals of the drive motor 200 areshorted and the generated back EMF counteracts the rotation of the drivemotor 200 allowing for faster stopping and greater positional precisionin adjusting the linear position of the firing rod 220.

In the constant speed mode, the speed calculator 422 in conjunction withthe microcontroller 500 and/or the motor driver adjust the rotationalspeed of the drive motor 200 to ensure constant linear speed of thefiring rod 220. The electronic clutching mode involves repeat engagementand/or disengagement of the clutch 300 from the drive motor 200 inresponse to sensed feedback signals from the position and speedcalculators 416 and 422. In controlled current activation mode, thecurrent is either ramped up or down to prevent damaging current andtorque spiked when transitioning between static to dynamic mode toprovide for so-called “soft start” and “soft stop.”

The data storage module 502 records the data from the sensors coupled tothe microcontroller 500. In addition, the data storage module 502records the identifying code of the loading unit 169, the status of theend effector 100, number of stapling cycles during the procedure, etc.The data storage module 502 is also configured to connect to an externaldevice such as a personal computer, a PDA, a smartphone, a storagedevice (e.g., Secure Digital® card, Compact Flash® card, MemoryStick®,etc.) through a wireless or wired data port 503. This allows the datastorage module 502 to transmit performance data to the external devicefor subsequent analysis and/or storage. The data port 503 also allowsfor so-called “in the field” upgrades of firmware of the microcontroller500.

A feedback control system 601 is shown in FIGS. 21-22. The systemincludes a feedback controller 603 which is shown in FIGS. 22A-B. Theinstrument 10 is connected to the feedback controller 603 via the dataport 502 which may be either wired (e.g., Firewire®, USB®, SerialRS232®, Serial RS485®, USART®, Ethernet®, etc.) or wireless (e.g.,Bluetooth®, ANT3®, KNX®, ZWave®, X10® Wireless USB®, IrDA®, Nanonet®,Tiny OS®, ZigBee®, 802.11 IEEE, and other radio, infrared, UHF, VHFcommunications and the like).

With reference to FIG. 21, the feedback controller 603 is configured tostore the data transmitted thereto by the instrument 10 as well asprocess and analyze the data. The feedback controller 603 is alsoconnected to other devices, such as a video display 604, a videoprocessor 605 and a computing device 606 (e.g., a personal computer, aPDA, a smartphone, a storage device, etc.). The video processor 605 isused for processing output data generated by the feedback controller 603for output on the video display 604. The computing device 606 is usedfor additional processing of the feedback data. In one embodiment, theresults of the sensor feedback analysis performed by the microcontroller600 may be stored internally for later retrieval by the computing device606.

The feedback controller 603 includes a data port 607 (FIG. 22B) coupledto the microcontroller 600 which allows the feedback controller 603 tobe connected to the computing device 606. The data port 607 may providefor wired and/or wireless communication with the computing device 606providing for an interface between the computing device 606 and thefeedback controller 603 for retrieval of stored feedback data,configuration of operating parameters of the feedback controller 603 andupgrade of firmware and/or other software of the feedback controller603.

The feedback controller 603 is further illustrated in FIGS. 22A-B. Thefeedback controller 603 includes a housing 610 and a plurality of inputand output ports, such as a video input 614, a video output 616, and aheads-up (“HUD”) display output 618. The feedback controller 603 alsoincludes a screen 620 for displaying status information concerning thefeedback controller 603.

Components of the feedback controller 603 are shown in FIG. 23. Thefeedback controller 603 includes a microcontroller 600 and a datastorage module 602. The microcontroller 600 and the data storage module602 provide a similar functionality as the microcontroller 500 and thedata storage module 502 of the instrument 10. Providing these componentsin a stand-alone module, in the form of the feedback controller 603,alleviates the need to have these components within the instrument 10.

The data storage module 602 may include one or more internal and/orexternal storage devices, such as magnetic hard drives, flash memory(e.g., Secure Digital® card, Compact Flash® card, MemoryStick®, etc.).The data storage module 602 is used by the feedback controller 603 tostore feedback data from the instrument 10 for later analysis of thedata by the computing device 606. The feedback data includes informationsupplied by the sensors disposed within the instrument 10 and the like.

The microcontroller 600 is configured to supplant and/or supplement thecontrol circuitry, if present, of the instrument 10. The microcontroller600 includes internal memory which stores one or more softwareapplication (e.g., firmware) for controlling the operation andfunctionality of the instrument 10. The microcontroller 600 processesinput data from the user interface 120 and adjusts the operation of theinstrument 10 in response to the inputs. The microcontroller 600 iscoupled to the user interface 120 via a user feedback module 504 whichis configured to inform the user of operational parameters of theinstrument 10. More specifically, the instrument 10 is configured toconnect to the feedback controller 603 wirelessly or through a wiredconnection via a data port 407 (FIG. 6).

In a disclosed embodiment, the microcontroller 600 is connected to thedrive motor 200 and is configured and arranged to monitor the batteryimpedance, voltage, temperature and/or current draw and to control theoperation of the instrument 10. The load or loads on battery 400,transmission, drive motor 200 and drive components of the instrument 10are determined to control a motor speed if the load or loads indicate adamaging limitation is reached or approached. For example, the energyremaining in battery 400, the number of firings remaining, whetherbattery 400 must be replaced or charged, and/or approaching thepotential loading limits of the instrument 10 may be determined. Themicrocontroller 600 may also be connected to one or more of the sensorsof the instrument 10 discussed above.

The microcontroller 600 is also configured to control the operation ofdrive motor 200 in response to the monitored information. Pulsemodulation control schemes, which may include an electronic clutch, maybe used in controlling the instrument 10. For example, themicrocontroller 600 can regulate the voltage supply of the drive motor200 or supply a pulse modulated signal thereto to adjust the powerand/or torque output to prevent system damage or optimize energy usage.

In one embodiment, an electric braking circuit may be used forcontrolling drive motor 200, which uses the existing back electromotiveforce of rotating drive motor 200 to counteract and substantially reducethe momentum of drive tube 210. The electric braking circuit may improvethe control of drive motor 200 and/or drive tube 210 for stoppingaccuracy and/or shift location of powered surgical instrument 10.Sensors for monitoring components of powered surgical instrument 10 andto help prevent overloading of powered surgical instrument 10 mayinclude thermal-type sensors, such as thermal sensors, thermistors,thermopiles, thermo-couples and/or thermal infrared imaging and providefeedback to the microcontroller 600. The microcontroller 600 may controlthe components of powered surgical instrument 10 in the event thatlimits are reached or approached and such control can include cuttingoff the power from the power source 400, temporarily interrupting thepower or going into a pause mode and/or pulse modulation to limit theenergy used. The microcontroller 600 can also monitor the temperature ofcomponents to determine when operation can be resumed. The above uses ofthe microcontroller 600 may be used independently of or factored withcurrent, voltage, temperature and/or impedance measurements.

The result of the analysis and processing of the data by themicrocontroller 600 is output on video display 604 and/or the HUDdisplay 622. The video display 604 may be any type of display such as anLCD screen, a plasma screen, electroluminescent screen and the like. Inone embodiment, the video display 604 may include a touch screen and mayincorporate resistive, surface wave, capacitive, infrared, strain gauge,optical, dispersive signal or acoustic pulse recognition touch screentechnologies. The touch screen may be used to allow the user to provideinput while viewing operational feedback. The HUD display 622 may beprojected onto any surface visible to the user during surgicalprocedures, such as lenses of a pair of glasses and/or goggles, a faceshield, and the like. This allows the user to visualize vital feedbackinformation from the feedback controller 603 without losing focus on theprocedure.

The feedback controller 603 includes an on-screen display module 624 anda HUD module 626. The modules 626 process the output of themicrocontroller 600 for display on the respective displays 604 and 622.More specifically, the OSD module 624 overlays text and/or graphicalinformation from the feedback controller 603 over other video imagesreceived from the surgical site via cameras disposed therein. Themodified video signal having overlaid text is transmitted to the videodisplay 604 allowing the user to visualize useful feedback informationfrom the instrument 10 and/or feedback controller 603 while stillobserving the surgical site.

FIGS. 24-25 illustrate another embodiment of the instrument 10′. Theinstrument 10′ includes a power source 400′ having a plurality of cells401 arranged in a straight configuration. The power source 400′ isinserted vertically into a vertical battery chamber 800 within thehandle portion 112. The battery chamber 800 includes a spring 802 withinthe top portion thereof to push downward the power source 400′. In oneembodiment, the spring 802 may include contacts to electrically couplewith the power source 400′. The power source 400′ is held within thebattery chamber 800 via a battery cap 804 which is configured to slidein a distal direction to lock in place. The cap 804 and the handle 112may include tongue and groove couplings to keep the cap 804 from slidingout. The power source 400′ is biased against the cap 804 due to thedownward force of the spring 802. As the cap 804 is slid in a proximaldirection, the power source 400′ is ejected from the battery chamber 800by the spring 802.

FIG. 25 shows another embodiment of the rotational sensor 239 whichdetects the rotation of the drive tube 210, thus, measuring the rate ofrotation of the drive tube 210 which allows for determination of thelinear velocity of the firing rod 220. The rotational sensor 239includes an encoder wheel 810 mounted to drive tube 210 and an opticalreader 812 (e.g., photo interrupter). The optical reader 812 isconfigured to determine the number of interruptions in a light beamwhich is continuously provided between two opposing edges 814 and 816thereof. The wheel 810 rotates with the drive tube 210 and includes aplurality of slits 811 therethrough.

The outer edge of the wheel 810 is disposed between the opposing edgesof the optical reader 812 such that the light being transmitted betweenthe edges 814 and 816 shine through the slits 811. In other words, thelight beam between the edges 814 and 816 is interrupted by the wheel 810as the drive tube 210 is rotated. The optical reader 812 measures thenumber of interruptions in the light beam and rate of occurrencesthereof and transmits these measurements to the speed calculator 422which then determines the speed of the drive rod 220 as discussed above.

FIGS. 27-32 show the instrument 10′ having a retraction assembly 820 forretracting the firing rod 220 from its fired position. The retractionassembly 820 provides for a manually driven mechanical interface withthe drive tube 210 allowing for manual retraction of the firing rod 210via ratcheting action of the retraction assembly 820 in emergencysituations (e.g., electrical malfunction, stuck end effector 160, etc.).The retraction assembly 820 may be configured as a modular assemblywhich can be inserted into the instrument 10′.

With reference to FIG. 30, the retraction assembly 820 includes aretraction chassis 822 having top portion 823 and a bottom portion 825.The retraction assembly 820 interfaces mechanically with the drive tube210 via a drive gear 826 and a retraction gear 824. The drive gear 826is attached to the drive tube 210 and is translated in response to therotation of the drive tube 210. Conversely, rotation of the drive gear826 imparts rotation on the drive tube 210. The drive gear 826 and theretraction gear 824 may be bevel gears allowing the gears 824 and 826 tointerface in a perpendicular manner.

The retraction gear 824 is coupled to a first spindle 828 which isdisposed in a substantially perpendicular manner between the top andbottom portions 823 and 825 of the retraction chassis 822 and isrotatable around a longitudinal axis defined thereby. The first spindle828 further includes a first spur gear 830 attached thereto and to theretraction gear 824. The first spur gear 830 interfaces with a secondspur gear 832 disposed on a second spindle 834 which is also is disposedin a substantially perpendicular manner between the top and bottomportions 823 and 825 of the retraction chassis 822 and is rotatablearound a longitudinal axis defined thereby.

The second spur gear 832 interfaces mechanically with a third spur gear836 which is disposed on the first spindle 828. The third spur gear 836is attached to a first clutch portion 838 of a unidirectional clutchassembly 840. The clutch assembly 840 further includes a second clutchportion 840 rotatably disposed on the first spindle 828 above the firstclutch portion 838 with a spring 843 disposed between the first andsecond clutch portions 838 and 840 thereby keeping the first and secondclutch portions 838 and 840 in a raised non-interlocking configuration(e.g., first configuration) as shown in FIG. 31.

Rotation of the drive tube 210 and/or the drive gear 826 impartsrotation on the retraction gear 824 and the first, second and third spurgears 830, 832 and 836 along with the first portion 838 and therespective spindles 828 and 834. Since, the second clutch portion 842can rotate about the spindle 828 and is separated from the first clutchportion 838 by the spring 843, the rotation of the first portion 838 isnot translated thereto.

The first and second clutch portions 838 and 842 include a plurality ofinterlocking teeth 844 having a flat interlocking surface 846 and asloping slip surface 848. In a second configuration as shown in FIG. 32,the second clutch portion 842 is pushed downwards by a retraction lever845 thereby interfacing the teeth 844. The slip surfaces 848 allow forthe interlocking surfaces 846 to come in contact with each other therebyallowing rotation of the second clutch portion 842 to rotate the firstclutch portion 838 and all of the interfacing gears.

The retraction lever 845 includes a camming portion 847 and a handle 849attached thereto. The camming portion 847 includes an opening 853 whichhouses a unidirectional needle clutch 855 which is mechanicalcooperation with a fitting 856 attached to the first spindle 828 therebyallowing the retraction lever 845 to rotate about the first spindle 828.With reference to FIG. 29, the lever 845 includes a one or more cammingmembers 850 having a camming surface 852. In the first configuration,the lever 845 is disposed along a lever pocket 860 of the housing 110 asshown in FIG. 27. The lever 845 is pushed up by the spring 843 againstthe top portion 823 and the camming members 850 are disposed withincorresponding cam pockets 858. The lever 845 is maintained in the firstconfiguration by a return extension spring 862 mounted between the topportion 823 and the camming portion 847. The camming members 850 and thelever pocket 860 prevent further rotation of the lever 845.

As the lever 845 is pulled out of the lever pocket 860, the cammingmembers 850 interface with the corresponding cam pockets 823 and pushthe camming portion 847 of the lever 845 in a downward direction. Thedownward movement compresses the spring 843 and pushes the first andsecond clutch portions 838 and 842 together interlocking the teeth 844thereby engaging the portions 838 and 842. Rotation of the cammingportion 847 in a counterclockwise direction actuates the needle clutch855 which interfaces with the fitting 856 and the first spindle 828.Continual rotation of the lever 845 rotates the clutch assembly 840which in turn rotates the spur gears 836, 832 and 830 and the retractionand drive gears 824 and 826. This in turn rotates drive tube 210 andretracts the drive rod 220.

The lever 845 can be rotated for a predetermined amount until the handle849 abuts the housing 110 as shown in FIG. 28. Thereafter, the lever 845is brought back to its first configuration by the return extensionspring 862. This raises the camming portion 847 allowing the secondclutch portion 842 to also move upward and disengage the first clutchportion 838. The needle clutch 855 releases the fitting 856 allowing thelever 845 to return to the first configuration without affecting themovement of the drive tube 210. Once the lever 845 is returned to thefirst configuration, the lever 845 may be retracted once again tocontinue to ratchet the driving rod 220.

Referring to FIGS. 33 and 34, the end effector 160 includes a first jawmember 902, a second jaw member 904, and a knife 906. The first andsecond jaw members 902, 904 are moveable relative to one another betweenan open position and a clamped position. In the clamped position, tissuemay be grasped or clamped within the end effector 106 between the firstand second jaw members 902, 904. The knife 906 is moveable through thefirst and second jaw member 902, 904 along a longitudinal axis of theend effector 160 to sever tissue clamped within the end effector 160.

The end effector 160 includes a detection assembly 910 provided inaccordance with the present disclosure that detects or senses propertiesof tissue clamped within the end effector 160 before the knife 906 isactuated to sever tissue clamped within the end effector 160. Thedetection assembly 910 may prevent or lockout the knife 906 fromactuating based on sensed tissue properties. The detection assembly 910analyzes the clamped tissue to determine one or more attributes of theclamped tissue including, but not limited to, the thickness of clampedtissue, the type of clamped tissue, or the presence of vasculaturewithin clamped tissue. As such, the detection assembly 910 may preventthe knife 906 from severing tissue if undesired tissue (e.g., bowels) isclamped within the end effector 160. The detection assembly 910 maydetect the high vascularity of the undesired tissue as compared to thelow vascularity of the desired tissue (e.g., adhesions).

With continued reference to FIGS. 33 and 34, the detection assembly 910includes a light source 912, a light sensor 914, and a processor 918.The light source 912 is disposed within the first jaw member 902 and thelight sensor 914 is disposed within the second jaw member 904 inopposition to the light source 912. As shown, the light source 912 andthe light sensor 914 are each positioned adjacent a distal end of one ofthe first and second jaw members 902, 904; however, it is contemplatedthat the light source 912 and the light sensor 914 may be positioned inopposition to one another anywhere along tissue contacting surfaces ofthe first and second jaw members 902, 904. As detailed below, whentissue is clamped within the end effector 160, the light source 912emits light through the clamped tissue towards the light sensor 914 thatoptically senses properties of light transmitted through the clampedtissue. It is contemplated that the light source 912 may emit light andthe light sensor 914 may sense properties of light before, during,and/or after actuation of the knife 906.

The light source 912 may generate light by a variety of means including,but not limited to, electron-stimulation, incandescent lamps,electroluminescent, gas discharge, high-intensity discharge, lasers,chemoluminescence, fluorescence, and/or phosphorescence. The lightsource 912 may be a light emitting diode (LED). The light emitted fromthe light source 912 may be in the visual and/or infrared spectrum. Thelight source 912 may be activated as the switch 114 (FIG. 1) isdepressed. The light may be transmitted by a fiber optic cable

The light sensor 914 is configured to optically sense properties oflight in contact therewith. The light sensor 914 may be configured todetect a specific chemical or agent injected into the blood stream of apatient including, but not limited to, chemicals or agents capable ofbioluminescence, radioluminescence, chemoluminescence, fluorescence,and/or phosphorescence. Further, the light sensor 914 may senseproperties of light indicating foreign bodies, diseased tissue, ornon-tissue within clamped tissue.

The light sensor 914 converts the optically sensed properties of lightto data signals that are transmitted to the processor 918. It iscontemplated that the light sensor 914 may be wired directly to orwirelessly connected to the processor 918.

The wireless connection may be via radio frequency, optical, WIFI,Bluetooth® (an open wireless protocol for exchanging data over shortdistances (using short length radio waves) from fixed and mobiledevices, creating personal area networks (PANs)), ZigBee® (aspecification for a suite of high level communication protocols usingsmall, low-power digital radios based on the IEEE 802.15.4-2003 standardfor wireless personal area networks (WPANs)), etc.

The processor 918 analyzes the data signals received from the lightsensor 914 to determine attributes of the tissue clamped within the endeffector 160. The processor 918 may display the tissue attributes on theuser interface 120 (FIG. 3) (e.g., screen 122).

The processor 918 compares the calculated tissue attributes topredetermined accepted values before and/or during actuation of theknife 906. The processor 918 may prevent or lockout the knife 906 fromactuating if one or more of the calculated tissue attributes are notwithin a predetermined range of acceptable values. The processor 918 mayalso retract the knife if one or more of the calculated tissueattributes is not within a predetermined range of acceptable values. Theprocessor 918 may also provide feedback to a user when a calculatedtissue attribute is not within the predetermined range of acceptablevalues. The feedback may be audible, haptic, or visual indicia asdetailed above.

The processor 918 may calculate the thickness of clamped tissue from theintensity of the light transmitted through the clamped tissue. Theprocessor 918 may calculate the thickness of various known tissue types(i.e., lung, stomach, intestinal, muscular, etc.) from the intensity ofthe light transmitted through the clamped tissue. The light sensor 914may sense multiple wavelengths of light and the processor 918 maydetermine the type of clamped tissue from the intensity or optical powerof each wavelength sensed by the light sensor 914. In addition, theprocessor 918 may determine the vasculature of clamped tissue from theintensity of light, at specific wavelengths, absorbed by the clampedtissue.

The tissue thickness may be determined by the red blood cell densitywithin the tissue. For example, if there is too much blood occlusion inthe clamped tissue, the reduced density of red blood cells is indicativethat the clamped tissue is too thick or includes too much vasculaturefor the knife 906 to safely sever.

The attributes of clamped tissue may also be detected by detectingabnormal blood flow. For example, abnormal blood flow may indicate thatcancerous or tumorous tissue is clamped within the end effector 160. Insuch instances, the processor 918 may inform a clinician that aresection margin (i.e., the amount of tissue being removed containingcancerous or tumorous tissue) should be increased.

As shown, the processor 918 is disposed within the second jaw member904; however, it is contemplated that the processor 918 may be disposedwithin the first jaw member 902 or anywhere within the surgicalinstrument 10 (FIG. 1) (e.g., within the body portion 168 or housing110) or external to the surgical instrument 10. It is also contemplatedthat the processor 918 may be integrated into the microcontroller 500(FIG. 6).

Additionally or alternatively, the processor 918 may allow or enablefiring of the staple cartridge 164 if a calculated tissue attribute iswithin the predetermined range of values. The processor 918 may provideaudible, haptic, or visual indicia to the clinician to alert theclinician that the calculated tissue attribute is within thepredetermined range of values (e.g., a green light, a go ahead tone, ago icon, a go light pattern, an audible go pattern, etc.).

Referring to FIG. 35, another detection assembly 910 is provided inaccordance with the present disclosure and includes a light source 912and a light sensor 914 disposed adjacent one another in each of thefirst and second jaw member 902, 904 with the light source 912 of thefirst jaw member 902 opposing the light sensor 914 of the second jawmember 904 and the light source 912 of the second jaw member 904opposing the light sensor 914 of the first jaw member 902. In such aconfiguration, the light sensors 914 may sense light reflected from thetissue clamped within the end effector 160 in addition to lighttransmitted through the clamped tissue. One of the light sources 912 mayemit light having a first wavelength and the other of the light sources912 may emit light having a second wavelength (e.g., the light source912 of the first jaw member 902 may emit light in the visual spectrumand the light source 912 of the second jaw member 904 may emit light inthe infrared spectrum) allowing the processor 918 to determine if theattributes of light sensed by each light sensor 914 is an attribute oftransmitted or reflected light indicating absorption of knownwavelengths within the tissue.

Referring to FIG. 36, yet another the detection assembly 910 is providedin accordance with the present disclosure and includes two light sources912 and a light sensor 914 disposed within the first jaw member 902 withthe light sensor 914 disposed between the light sources 912. The lightsensor 914 senses light attributes of light emitted from the lightsources 912 and reflected off of tissue clamped within the end effector160. Due to the relative proximity of light sources 912 it may bedesirable to include a light blocking shade between the light sources toenhance the depth of light penetration within the tissue. As shown, thesecond jaw member 904 does not include a light source or a light sensor;however, it is contemplated that the second jaw member 904 may include alight source 912 opposing the light sensor 914 of the first jaw member902 and two light sensors 914 with each opposing one of the lightsources 912 of the first jaw member 902.

With reference to FIG. 37, the responsivity of light transmitted throughtissue as detected by light sensors (e.g., light sensors 914) sensitiveto different wavelengths of light as indicated by the labels “CLEAR,”“RED,” “BLUE,” and “GREEN.” As shown, the intensity of the wavelength oflight may be used to determine the color of the tissue clamped withinthe end effector 160. It will be appreciated that when the light istransmitted through tissue clamped within the end effector 160, thewavelength corresponding to the color of the tissue is not transmittedthrough the tissue such that the wavelengths of transmitted light may beanalyzed to determine the color of the clamped tissue.

Referring to FIGS. 38 and 39, another detection assembly 920 inaccordance with the present disclosure includes an ultrasound probe 922and a processor 928. The ultrasound probe 922 is disposed in one of thejaw members 902, 904 adjacent a distal end of the thereof. Similar tothe detection assembly 910 detailed above, the detection assembly 920detects or senses properties of tissue clamped within the end effector160 before the knife 906 is actuated to sever tissue clamped within theend effector 160, as such only the differences will be detailed herein.

The ultrasound probe 922 includes an ultrasonic transducer 924 and anultrasound sensor 926. The ultrasonic transducer 924 converts electricalenergy to sound wave energy. The ultrasonic transducer 924 may convertelectrical energy to sound wave energy with piezoelectric crystals. Thesound wave energy is directed towards tissue adjacent the ultrasoundprobe 922 with some of the sound wave energy being reflected backtowards the ultrasound probe 922. The ultrasound sensor 926 senses thesound wave energy reflected back towards the ultrasound probe 922 todevelop a sonogram of the tissue adjacent the ultrasound probe 922.

The ultrasound sensor 926 converts the sensed sound wave energy to datasignals that are sent to the processor 928. Similar to the processor 918of the detection assembly 910, the processor 928 may be disposed withinthe end effector 160, within the housing 168 of the surgical instrument10 (FIG. 1) (e.g., integrated with microprocessor 500), or remote to thesurgical instrument 10. The processor 928 displays the sonogram of thetissue adjacent the ultrasound probe 922 on a display (e.g., screen 122of the user interface 120 or a monitor remote to the surgical instrument10) to allow a clinician to visualize the tissue adjacent the ultrasoundprobe 922 before actuating the knife 906. During visualization of thetissue adjacent the ultrasound probe 922, a clinician is able tovisualize attributes of tissue clamped within the end effector 160 suchas areas of high density, areas of low density, foreign objects, and/orabnormal tissue before, during, and/or after actuating the knife 906.

Referring now to FIGS. 40-43, according to an embodiment of the presentdisclosure, microcontroller 405 controls the firing speed of staples 66(FIG. 9) ejected by the surgical instrument 10 based on measuredproperties of the tissue being stapled, the drive motor 200, and/orother components of the surgical instrument 10. In particular, duringfiring of the staples 66, microcontroller 405 sets an initial speed offiring rod 220 based on a clamp force being exerted on the targettissue.

As depicted in FIG. 40, clamp force may be measured directly by sensorsand/or calculated based on various sensor readings. In embodiments,force/load sensors, such as the strain sensor 185 or strain gauge sensor187, 189 may be used to measure the load on the firing rod 220 (FIG. 6)and/or other load bearing components of the instrument 10. Inembodiments, these sensors are coupled to the microcontroller 405.

Clamp force may also be determined based on voltage and current of theelectrical energy being supplied to the drive motor 200 using voltagesensors 428 (e.g., voltmeter) and/or current sensors 430 (e.g., ammeter)coupled to the drive motor 200. In embodiments, a torque sensor 431 mayalso be used to monitor torque of the drive motor 200. In furtherembodiments, proximity sensors 191 and 193, which are configured tomonitor proximity of the jaw members 162 and 164 may also be used todetermine clamp force. In further embodiments, temperature sensors 403(e.g., thermocouples, thermistors, etc.), which are coupled to variouscomponents of the instrument 10 (e.g., drive motor 200, the power source400, microcontroller 405, etc.) may be used to monitor temperature. Themicrocontroller 405 may store various transfer functions which correlatemeasured voltage, current, torque, proximity measurements, and/ortemperature to the clamp force. In particular, current draw and torqueof the motor 200, which may be determined by the voltage and/or currentsensors 428, 430 and torque sensors 431, respectively, may be used tocorrelate work done by the drive motor 200 to the clamp force.Similarly, proximity of the jaw members 162 and 164 in conjunction withother sensor measurements may also be utilized to extrapolate the clampforce.

In addition, the firing force of the staples 66 may also be determinedby one or more of the sensors described above. In embodiments, currentsensor 430, voltage sensor 428, and/or torque sensors 431 coupled to thedrive motor 200 can be used such that measured properties, e.g.,voltage, current, and motor torque, can then be correlated with thefiring force of the staples 66. Peaks in current or voltage may be usedto indicate increases in force or changes in load conditions.

The microcontroller 405 is also configured to continually adjust thefiring speed based on the measured firing force of the staples 66 on thetarget tissue. Adjustment of the firing speed of the staples 66 from thecartridge assembly 162 optimizes staple formation. In particular,staples 66 fired with excess force or at excess speeds can producemalformed staples 66. Thus, adjustment of the firing speed helpsminimize the force exerted on target tissue during staple firing.

The clamp force exerted on tissue during staple firing by the surgicalinstrument 10 based on an algorithm executed by the microcontroller 405is illustrated in FIG. 41. The staple firing is described in threestages 900, 902, and 904. At stage 900, a user of instrument 10initially clamps the end effector 160 on a target tissue, which isillustrated by an increase in the clamp force over time until the userclamps the end effector 160 on the target tissue. The microcontroller405 determines the initial clamp force based on one or more sensormeasurements, which is used to determine the starting firing speed. Inparticular, end effector 160 clamps the target tissue during whichmicrocontroller 405 employs a delay during the stage 902, or a asillustrated by a gap between the force required to clamp tissue andinitial force to begin firing after the wait time. Compression of thetarget tissue during the stage 902 reduces the amount of blood and fluidin the clamped tissue and provides for a more accurate maximum clampforce measurement. The stage 902 may be a predetermined time period setby a user or determined by microcontroller 405. After the stage 902, thestaples 66 from the cartridge assembly 162 are fired at an initialfiring speed.

Throughout the firing, the microcontroller 405 also continually monitorsand determines the firing force of the staples 66 during the stage 904,and subsequently adjusts the firing speed based on the force feedbackobtained during the stage 904. In particular, as shown in FIG. 41, themicrocontroller 405 continually adjusts the firing speed to reduce theforce exerted on the target tissue until a desired force is maintained.By continually adjusting the firing speed of the staples 66,microcontroller 405 minimizes the amount of force exerted on the tissueand optimizes staple formation.

FIG. 42 illustrates a flowchart of an algorithm executed bymicrocontroller 405 to control the surgical instrument 10 according toone embodiment of the present disclosure. Initially, at step 1002, drivemotor 200 causes the drive beam 266 of the axial drive assembly 213 toactuate the end effector 160, which causes the jaw members 162, 164 ofthe end effector 160 to clamp onto the target tissue (FIGS. 1-6). Inparticular, the pair of cam members 40 a of the retention flange 40engage the jaw members 162, 164 during longitudinal advancement of thedrive beam 266 (FIG. 8). At step 1004, sensors, e.g., strain gauges 187and 189 (FIG. 17) or any of the other sensors previously describedabove, determine a maximum clamp force of jaw members 162, 164 on thetarget tissue

Next, microcontroller 405 sets the initial firing speed of the staples66 released by the staple cartridge 164 based on the measured maximumclamp force. In particular, microcontroller 405 controls the speed atwhich the drive motor 200 advances the drive beam 213, therebycontrolling the speed at which the staples 66 are fired. Microcontroller405 first determines if the measured maximum clamp force falls withinone of a plurality of predetermined ranges. In the embodiment depictedin FIG. 42, microcontroller 405 contains four different predeterminedranges 1006, 1026, 1042, 1054. The ranges are defined by a firstthreshold (e.g., about 33 pound-force (lbf)), a second threshold (e.g.,about 72 lbf), and a third threshold (e.g., about 145 lbf). If the jawmembers 162 and 164 exert a maximum clamp force on the target tissuebelow the first threshold at step 1006, the microcontroller 405 sets theinitial firing speed of the staples 66 to a first speed (e.g., “FAST”speed) at step 1008. If the maximum clamp force is between the firstthreshold and the second threshold at step 1026, the microcontroller 405sets the initial firing speed of the staples 66 to a second speed(e.g.,“MEDIUM” speed) at step 1028. If the maximum clamp force isbetween the second threshold and the third threshold at step 1042, themicrocontroller 405 sets an initial firing speed of the staples 66 to athird speed (e.g., “SLOW” speed) at step 1044. Lastly, if the maximumclamp force is greater than the third threshold at step 1054, themicrocontroller 405 prevents the system from firing at 1056. The forcevalues for each of the ranges, the number of ranges and correspondingspeed settings that are described above are exemplary and may bemodified based on a variety of factors, such as the needs of theclinician, the surgical instrument 10 being used, procedure beingperformed, staples 66 being used, etc.

If the microcontroller 405 sets the initial firing speed to first,second, or third speeds, the microcontroller 405 continually monitorsthe force exerted on the tissue by the staples 66 as the staples 66 arefired, i.e., the firing force, and continually adjusts the firing speedof the staples 66, accordingly. In particular, during firing of thestaples 66, the microcontroller 405 continually monitors and adjusts thefiring speed based on whether the measured firing force falls within apredetermined range. As depicted in FIG. 42, if the initial firing speedis set to the first speed (e.g.“FAST”) at step 1008 and themicrocontroller 405 subsequently determines that the firing force isless than a first threshold (e.g., 65 lbf) at step 1010, themicrocontroller 405 maintains the firing speed at the preset first speedat 1012. However, if the firing force increases, such that it is betweenthe first threshold (e.g., 65 lbf) and a second threshold (e.g., 80 lbf)at step 1014, the microcontroller 405 adjusts the firing speed to thesecond speed (e.g. “MEDIUM”) at step 1016. However, if the firing forceis between the second threshold and a third threshold (e.g., 145 lbf) atstep 1018, the microcontroller 405 adjusts the firing speed to the thirdspeed (e.g.,“SLOW”) at step 1020. If the firing force rises above thethird threshold at step 1022, the microcontroller 405 stops the firingof the staples 66 at step 1024. This can occur when the staples 66 havecompleted firing or if the staples 66 encounter an unknown obstruction.This feature can prevent damage to the instrument 10 and/or the tissue.

In embodiments when the initial firing speed is set to the second speed(e.g., “MEDIUM”) or the third speed (e.g., “SLOW”) at steps 1028 and1044, microcontroller 405 adjusts the firing forces by modifying thethreshold ranges. With respect to the particular embodiment depicted inFIG. 42, if the initial firing speed is set to the second speed at step1028 and the firing force remains below the second threshold at step1030, the microcontroller 405 keeps the firing speed at the second speedat step 1032. However, the microcontroller 405 changes the firing speedto the third speed at step 1036 if the firing force rises to be betweenthe second threshold and the third threshold at step 1034. Likewise, ifthe initial firing speed is set to the third speed at step 1044 and thefiring force remains below the third threshold at step 1048, themicrocontroller 405 keeps the firing speed at the third threshold atstep 1048. In all three cases, if the initial firing speed is set basedon either the first, second, or third thresholds and the firing forcerises above the third threshold at steps 1022, 1038, and 1050, themicrocontroller 405 stops the firing of any further staples 66 at steps1024, 1040, and 1052, respectively.

FIG. 43 depicts a graphical representation of exemplary firing speedsand forces based on the algorithm described above with respect to FIG.42. In particular, FIG. 43 depicts firing speed (on the y-axis) versusfiring force (on the x-axis). As detailed above, the microcontroller 405determines an initial firing speed (e.g., “FAST” (1100), “MEDIUM”(1102), or “SLOW” 1104) based on an initial clamp force. In FIG. 43, theinitial clamp force is grouped into one of three groups: Group 1 if theclamp force is below the first threshold (e.g., 33 lbf); Group 2 if theclaim force is between the first threshold and the second threshold(e.g., 72 lbf); and Group 3 if the clamp force is between the secondthreshold and the third threshold (e.g., 145 lbf). In the embodimentdepicted in FIG. 43, the initial firing speed is set to the first speed(e.g., “FAST”) for Group 1, the second speed (e.g., “MEDIUM”) for Group2, and (e.g., “SLOW”) for Group 3. Once the initial firing speed is set,microcontroller 405 adjusts the firing speed based on the measuredfiring force. As shown in FIG. 43, if the firing force exceeds the firstthreshold (e.g., 65 lbf), the initial firing speed drops from the firstspeed to the second speed. If the firing speed exceeds the secondthreshold (e.g., 80 lbf), the initial firing speed drops from the secondspeed to the third speed, and if the firing speed exceeds the thirdthreshold (e.g., 145 lbf), the microcontroller 405 stops firing of thestaples 66.

The above disclosure describes a predictive style adaptive staplingalgorithm that optimizes staple formation and minimizes force duringfiring of a staple from a powered surgical instrument, e.g., a surgicalstapler. Using the method described above, a surgeon clamps the jawmembers of the surgical instrument on tissue, the clamp force influencesthe utilization of a wait and hold time on the tissue as well as thestarting firing speed, and throughout the firing, the surgicalinstrument has the ability to slow down the firing speed based on forcefeedback. By controlling the firing speed by the surgical instrument,the above described method optimizes the firing force on target tissueand minimizes the percentage of malformed staples.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Any combination ofthe above embodiments is also envisioned and is within the scope of theappended claims. Therefore, the above description should not beconstrued as limiting, but merely as exemplifications of particularembodiments. Those skilled in the art will envision other modificationswithin the scope of the claims appended hereto.

What is claimed:
 1. A surgical stapler, comprising: a handle assembly;an end effector coupled to the handle assembly, the end effectorincluding: a first jaw member including a surgical fastener; and asecond jaw member including an anvil portion, at least one of the firstjaw member or the second jaw member is moveable relative to one anotherbetween an open position and a clamped position; a firing rod disposedin mechanical cooperation with the end effector; a drive motor coupledto the firing rod, the drive motor configured to advance the firing rodto cause the first and second jaw members to clamp tissue and to ejectthe surgical fastener; a sensor configured to measure a clamping forceexerted on tissue by the first and second jaw members; and a controlleroperatively coupled to the drive motor and configured to control a speedof the drive motor based on the measured clamping force.
 2. The surgicalstapler according to claim 1, wherein the controller is furtherconfigured to set the speed of the drive motor to a first firing speedin response to the measured clamping force being between a firstthreshold clamping force and a second threshold clamping force.
 3. Thesurgical stapler according to claim 2, wherein the first thresholdclamping force is about 0 pound-force (lbf) and the second thresholdclamping force is about 33 lbf.
 4. The surgical stapler according toclaim 2, wherein the first threshold clamping force is about 33 lbf andthe second threshold clamping force is about 72 lbf.
 5. The surgicalstapler according to claim 2, wherein the first threshold clamping forceis about 72 lbf and the second threshold clamping force is about 145lbf.
 6. The surgical stapler according to claim 1, wherein thecontroller is further configured to stop the drive motor in response tothe measured clamping force being greater than a first thresholdclamping force.
 7. The surgical stapler according to claim 6, whereinthe first threshold clamping force is about 145 lbf.
 8. The surgicalstapler according to claim 1, wherein the sensor is further configuredto measure a firing force exerted on the surgical fastener.
 9. Thesurgical stapler according to claim 8, wherein the controller is furtherconfigured to set the speed of the drive motor to a second firing speedin response to the measured firing force being between a first firingforce threshold and a second firing force threshold.
 10. The surgicalstapler according to claim 9, wherein the first firing force thresholdis about 0 lbf and the second firing force threshold is about 65 lbf.11. The surgical stapler according to claim 9, wherein the first firingforce threshold is about 65 lbf and the second firing force threshold isabout 80 lbf.
 12. The surgical stapler according to claim 9, wherein thefirst firing force threshold is about 80 lbf and the second firing forcethreshold is about 145 lbf.
 13. The surgical stapler according to claim9, wherein the controller stops the drive motor based on the firingforce being greater than a first firing force threshold.
 14. Thesurgical stapler according to claim 13, wherein the first firing forcethreshold is about 145 lbf.
 15. The surgical stapler according to claim1, wherein the sensor is a strain gauge sensor disposed on at least oneof the first jaw member, the second jaw member, or the firing rod. 16.The surgical stapler according to claim 1, wherein the sensor isconfigured to measure the clamping force by monitoring at least one of aspeed of the drive motor, a torque being applied by the drive motor, adistance between the first and second jaw members, a temperature of thedrive motor, or a load exerted on the firing rod.
 17. A method ofcontrolling the firing speed of a surgical stapler, the methodcomprising: positioning tissue between a first jaw member and a secondjaw member of an end effector, at least one of the first jaw member orthe second jaw member being moveable relative to one another, the firstjaw member including a staple cartridge; measuring a maximum clamp forceof the first and second jaw member on the tissue; setting a firing speedof a staple from the staple cartridge based on the measured maximumclamp force; initiating the firing of the staple from the staplecartridge; measuring a firing force exerted on the staple; and adjustingthe firing speed of the surgical stapler based on the measured firingforce.
 18. The method according to claim 17, further comprising stoppingthe firing of the staple from the staple cartridge in response to themeasured firing force being greater than a first firing force threshold.19. The method according to claim 18, wherein the first firing forcethreshold is about 145 pound-force (lbf).
 20. The method according toclaim 17, wherein the maximum clamp force is measured by a sensorconfigured to measure the clamping force by monitoring at least one of aspeed of the drive motor, a torque being applied by the drive motor, adistance between the first and second jaw members, or a load on thefiring rod.